i have grounded the vfd cable and am going to replace the crappy USB cable on the pokeys 57? if i still have a problem i am going to get a network unit..
i would like to keep the PMDX because it it totally reliable and connected to all the ins outs relays etc.?
what should i buy? if i get another stall after the new cable i want to buy something immediately. at least it is a stall and not a bit breaking runaway :)
about that, any ideas on how to stop bit breaking when the bit jams?
My Teco opens a relay on any fault including motor speed going below a threshold. So if the motor stalls it can stop the machine but mach 3 seems to continue current motion before estopping?
I am milling thousands of little beech blocks. 99.5% of them have similar hardness and grain but every once in a while one has rock hard grain and the router bit bogs down and basically stops while the massive servo motor breaks off the $40 bit. This is very rare but it did happen yesterday with a bit thta had cut just 100 parts ouch !!!
I sort of think I know the answer but what do others think?? I can connect the fault output to a relay that will cut power to the geckos. i sort of remember that the geckos do have an enable line so maybe i can just cut those instead?
?
?
Best regards, Spencer Chase 67550 Bell Springs Rd. Garberville, CA 95542 Postal service only. Laytonville, CA 95454 UPS only. Spencer@...Spencer@...Spencer@...(425) 791-0309 (707) 223-8212
------ Original Message ------
Sent: 3/28/2020 5:35:42 AM
Subject: Re: [MachCNC] strange stopping
Spenser, My Pokeys Mach-4 system had very similar problems when using USB.? My Pokeys also has an ethernet port and after switching to ethernet I have had zero problems. Bertho ? ? yes, i know i was talking about harnesses that are already made and taking them apart and twisting the wires.? however i am almost certain that the problem is not in the signal wires to the motors etc. all of that is properly grounded and there was never a problem before the Pokeys USB thing. whatever noise is getting in is through the USB, almost certainly. since the shield for the spindle motor power was not grounded at either end, i am hopeful that grounding it at the inverter will fix the problem. otherwise i need to deal with the usb cable or get some sort of isolator.? or just ditch the Pokeys and get a network device. Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212 ------ Original Message ------ Sent: 3/27/2020 9:02:28 PM Subject: Re: [MachCNC] strange stopping I did not mean to twist your existing wires. I was referring to when making harnesses using individual wires and then twisting the pair. Bertho ? ? i think it is all plugged into one outlet. will double check. not sure how i can twist wires at this point stuff is pretty mush in place but will look at the possibility. Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212 ------ Original Message ------ Sent: 3/27/2020 4:46:36 PM Subject: Re: [MachCNC] strange stopping A quick addition to John’s good comments: Make sure that all AC line cords are plugged into one wall outlet through a power strip. Using two different wall outlets can add a lot of unrelated noise. ? I am a firm believer in tightly twisted pair power and signal wires. It cancels out both electrostatic and inductive radiated and picked up signals. Bertho ? ? ? Electrical noise can be a bear.? Steve Spallings mentioned PC grounds and system or motor grounds.? I have his PMDX-126 and unfortunately the PC I'm using internally somewhere has the DC ground connected to the system frame which is the third earth prong on the power cord which then connects to the motor frames through the machine metal. The CUI encoders on the DC servos serve to further muck things up where their DC ground is connected to the frame.? Which is of course connected to the 3 prong and so DC ground earth ground are connected in several places.? Shielding has no rhyme or reason here but it's one place where a single ended connection for a shield is a bit more logical. ? My EE book on electrical noise states that the signal grounds should never be connected to the DC power grounds or frame.? The whole point of shielding is that it isolates the two. ? For your system also look at magnetic coupling.? The way a transformer works is a changing magnetic field introduces current in windings that are also in the magnetic field.? So the spindle motor current flowing through the wires can generate a field picked up encoder or limit switch wires.? Short of what is called mu metal shielding the only solution to electromagnetic interference is distance.? Route them far apart. ? Electrostatic shielding is different.? Twisted pairs help to null out electric field noise. Shielding can be grounded at one end or both of the frame (third prong) earth.? The point is you only want the noise current flowing back through the shield into the frame.? Not through your signal wires which includes the DC 0V wires.? People tend to forget what goes out a signal wire is still a signal as it comes back through what is commonly called the ground or common wire.? (Some manufacturers have called the +5V to +24V 'common' for limit switches) ? John Dammeyer. ? ? You are trying to fix a wrong schematic with cosmetic changes. You sure have a ground loop somewhere. Check your shields, they should be connected one side only with heavy short wire to good ground. Preferably star connection. ? i forgot to mention that, i have ferrites everywhere. that is one of the first things i do.? i have them on the signal leads to each stepper and even on the usb cable to the pokeys although the mfg suggested it would not do anything. i tried a usb signal conditioner thing but it did not work, meaning that most things plugged into it stopped working. anyone know of a signal conditioned for usb that does work? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212 ------ Original Message ------ Sent: 3/27/2020 4:03:12 AM Subject: Re: [MachCNC] strange stopping I would probably try adding ferrite beads to the leads. I have my router working really well with the following configuration. Solid state tiny computer running win 10. Mach 3 latest version Pokeys USB CNC thing connected to a PDMX. I am finally getting smooth motion no lost steps etc etc. Everything works except. Occasionally Mach3 just stops and is totally unresponsive. Can not reset, jog etc. The diag screen shows all ins and outs off. I have to kill Mach 3 and start again. I am pretty sure that every time it does this, when I restart the 4th axis DRO shows 4099.xxx? the 4th axix is angular.? I am running a gcode with a subroutine that repeats over and over with a tool change to allow inserting a new part for machining. i am also using the subroutine to make it possible to count parts.? when this failure happens is always close to the spindle motor going on or off. it is a three phase servo run by a high quality US inverter. Forgot the name right now but it is a good inverter not Chinese no name stuff. I am pretty sure the spindle motor is causing noise that kills the Pokeys. I have proper grounding and shielding.? I changed the inverter carrier frequency from the default of 5Khz to 2khz and have not had the problem yet but it some times does not happen for a considerable time.? any ideas? does the 4099 signify some overflow?? does it sound like it is inverter noise? might the lower carrier frequency be the fix? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
|
that is quite an expensive book but i just got it on ebay for $20 with shipping. the seller has two moer copies in case anyone else wants one. just search for the title on ebay and see who has it buy it now for $15.95 or so.
?
?
Best regards, Spencer Chase 67550 Bell Springs Rd. Garberville, CA 95542 Postal service only. Laytonville, CA 95454 UPS only. Spencer@...Spencer@...Spencer@...(425) 791-0309 (707) 223-8212
------ Original Message ------
Sent: 3/28/2020 2:10:28 AM
Subject: Re: [MachCNC] strange stopping
Thank you Keith for mentioning my favourite book on the subject.? As far as I'm concerned there is no better reference on how to deal with noise on anything from PC boards all the way up to entire rooms. John Dammeyer. ? ? ? Hi Spencer Have you tried a proper USB isolator in your USB connection? These range in price from a few dollars for a hobby grade device to around $100 for a proper industrial spec isolator such as the Advantech brand. I can’t recommend what to buy because my setup uses an Ethernet connection to my motion controller so is galvanically isolated by the transformers in the Ethernet ports. I must add that the fundamental physics behind shielding is not well understood and some of that misunderstanding is on display on this thread. Simplistically there are two sources of electromagnetic interference, electrostatic due to voltage and magnetic due to current flow. Electrostatic interference is typically mitigated by earthed screens or shields and in the first instance magnetic interference is mitigated by tightly twisted paired wiring. Cable shielding can also provide protection against magnetic interference but only if it is properly earthed at both ends. At this point arguments generally erupt about the folly of creating an earth loop. Creating a loop is deliberate and provides the mechanism for the magnetic shielding to work. The undesirable magnetic field causes current to flow around the loop which in turn radiates its own magnetic field. The two magnetic fields are in opposite directions and add together giving a resultant tending towards zero.? Rather than attempting to explain this further I would refer group members to a world renowned expert: Henry W Ott and his highly regarded textbook “Noise Reduction Techniques in Electronic Systems” and further, to carefully read installation instructions for VFDs from reputable manufacturers such as ABB, Siemens, Rockwell etc. Good quality VFDs usually have a substantial clamping arrangement for earthing the shield of the motor cable close to the VFD terminals.? The cable shield should also be well earthed to the motor terminal box using a good quality EMC grounding gland. Good quality shielded VFD cable and EMC glands are available from Lapp Kabel and other specialist manufacturers. ? Good luck and regards Keith Fisk.
|
It sounds like nothing might be wrong now. The big mistake was thinking that the VFD cable shield was grounded whereas it never was. It is now grounded at both ends and since it has no signal wires in it, ground loop is not an issue. I am just trying to not radiate the high frequency noise from the wires within.
The VFD instructions were not very clear about grounding but recommended all sorts of expensive reactors or whatever. I thought this was to keep noise out of the power line. Never had a problem with the parallel port so never did anything about that.
My hope is that it was just the ungrounded shield and that all will work fine now. If f not I do want tot ry a USB isolator and or better cable but as I said the one i tried would not power the Pokeys.?
so does anyone know of one that will work?? I don't want to spend $100 as that would be a big part of a network based controller that will work fine and have much greater capabilities as well.
recommendation for one of them?
unfortunately the USB cable is directly connected to the Pokeys and does not look like anything special, no ferrites and the cable is really thin suggeting not very good shielding.
it it worth replacing this with a better one with ferrites at both ends?
?
?
Best regards, Spencer Chase 67550 Bell Springs Rd. Garberville, CA 95542 Postal service only. Laytonville, CA 95454 UPS only. Spencer@...Spencer@...Spencer@...(425) 791-0309 (707) 223-8212
------ Original Message ------
Sent: 3/28/2020 1:28:59 AM
Subject: Re: [MachCNC] strange stopping
Hi Spencer Have you tried a proper USB isolator in your USB connection? These range in price from a few dollars for a hobby grade device to around $100 for a proper industrial spec isolator such as the Advantech brand. I can’t recommend what to buy because my setup uses an Ethernet connection to my motion controller so is galvanically isolated by the transformers in the Ethernet ports. I must add that the fundamental physics behind shielding is not well understood and some of that misunderstanding is on display on this thread. Simplistically there are two sources of electromagnetic interference, electrostatic due to voltage and magnetic due to current flow. Electrostatic interference is typically mitigated by earthed screens or shields and in the first instance magnetic interference is mitigated by tightly twisted paired wiring. Cable shielding can also provide protection against magnetic interference but only if it is properly earthed at both ends. At this point arguments generally erupt about the folly of creating an earth loop. Creating a loop is deliberate and provides the mechanism for the magnetic shielding to work. The undesirable magnetic field causes current to flow around the loop which in turn radiates its own magnetic field. The two magnetic fields are in opposite directions and add together giving a resultant tending towards zero.? Rather than attempting to explain this further I would refer group members to a world renowned expert: Henry W Ott and his highly regarded textbook “Noise Reduction Techniques in Electronic Systems” and further, to carefully read installation instructions for VFDs from reputable manufacturers such as ABB, Siemens, Rockwell etc. Good quality VFDs usually have a substantial clamping arrangement for earthing the shield of the motor cable close to the VFD terminals.? The cable shield should also be well earthed to the motor terminal box using a good quality EMC grounding gland. Good quality shielded VFD cable and EMC glands are available from Lapp Kabel and other specialist manufacturers. ? Good luck and regards Keith Fisk.
|
Spenser, My Pokeys Mach-4 system had very similar problems when using USB.? My Pokeys also has an ethernet port and after switching to ethernet I have had zero problems. Bertho ?
toggle quoted message
Show quoted text
From: [email protected] < [email protected]> On Behalf Of spencer@... Sent: Saturday, March 28, 2020 01:05 To: [email protected]Subject: Re: [MachCNC] strange stopping ? yes, i know i was talking about harnesses that are already made and taking them apart and twisting the wires.? however i am almost certain that the problem is not in the signal wires to the motors etc. all of that is properly grounded and there was never a problem before the Pokeys USB thing. whatever noise is getting in is through the USB, almost certainly. since the shield for the spindle motor power was not grounded at either end, i am hopeful that grounding it at the inverter will fix the problem. otherwise i need to deal with the usb cable or get some sort of isolator.? or just ditch the Pokeys and get a network device. Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212 ------ Original Message ------ Sent: 3/27/2020 9:02:28 PM Subject: Re: [MachCNC] strange stopping I did not mean to twist your existing wires. I was referring to when making harnesses using individual wires and then twisting the pair. Bertho ? ? i think it is all plugged into one outlet. will double check. not sure how i can twist wires at this point stuff is pretty mush in place but will look at the possibility. Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212 ------ Original Message ------ Sent: 3/27/2020 4:46:36 PM Subject: Re: [MachCNC] strange stopping A quick addition to John’s good comments: Make sure that all AC line cords are plugged into one wall outlet through a power strip. Using two different wall outlets can add a lot of unrelated noise. ? I am a firm believer in tightly twisted pair power and signal wires. It cancels out both electrostatic and inductive radiated and picked up signals. Bertho ? ? ? Electrical noise can be a bear.? Steve Spallings mentioned PC grounds and system or motor grounds.? I have his PMDX-126 and unfortunately the PC I'm using internally somewhere has the DC ground connected to the system frame which is the third earth prong on the power cord which then connects to the motor frames through the machine metal. The CUI encoders on the DC servos serve to further muck things up where their DC ground is connected to the frame.? Which is of course connected to the 3 prong and so DC ground earth ground are connected in several places.? Shielding has no rhyme or reason here but it's one place where a single ended connection for a shield is a bit more logical. ? My EE book on electrical noise states that the signal grounds should never be connected to the DC power grounds or frame.? The whole point of shielding is that it isolates the two. ? For your system also look at magnetic coupling.? The way a transformer works is a changing magnetic field introduces current in windings that are also in the magnetic field.? So the spindle motor current flowing through the wires can generate a field picked up encoder or limit switch wires.? Short of what is called mu metal shielding the only solution to electromagnetic interference is distance.? Route them far apart. ? Electrostatic shielding is different.? Twisted pairs help to null out electric field noise. Shielding can be grounded at one end or both of the frame (third prong) earth.? The point is you only want the noise current flowing back through the shield into the frame.? Not through your signal wires which includes the DC 0V wires.? People tend to forget what goes out a signal wire is still a signal as it comes back through what is commonly called the ground or common wire.? (Some manufacturers have called the +5V to +24V 'common' for limit switches) ? John Dammeyer. ? ? You are trying to fix a wrong schematic with cosmetic changes. You sure have a ground loop somewhere. Check your shields, they should be connected one side only with heavy short wire to good ground. Preferably star connection. ? i forgot to mention that, i have ferrites everywhere. that is one of the first things i do.? i have them on the signal leads to each stepper and even on the usb cable to the pokeys although the mfg suggested it would not do anything. i tried a usb signal conditioner thing but it did not work, meaning that most things plugged into it stopped working. anyone know of a signal conditioned for usb that does work? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212 ------ Original Message ------ Sent: 3/27/2020 4:03:12 AM Subject: Re: [MachCNC] strange stopping I would probably try adding ferrite beads to the leads. I have my router working really well with the following configuration. Solid state tiny computer running win 10. Mach 3 latest version Pokeys USB CNC thing connected to a PDMX. I am finally getting smooth motion no lost steps etc etc. Everything works except. Occasionally Mach3 just stops and is totally unresponsive. Can not reset, jog etc. The diag screen shows all ins and outs off. I have to kill Mach 3 and start again. I am pretty sure that every time it does this, when I restart the 4th axis DRO shows 4099.xxx? the 4th axix is angular.? I am running a gcode with a subroutine that repeats over and over with a tool change to allow inserting a new part for machining. i am also using the subroutine to make it possible to count parts.? when this failure happens is always close to the spindle motor going on or off. it is a three phase servo run by a high quality US inverter. Forgot the name right now but it is a good inverter not Chinese no name stuff. I am pretty sure the spindle motor is causing noise that kills the Pokeys. I have proper grounding and shielding.? I changed the inverter carrier frequency from the default of 5Khz to 2khz and have not had the problem yet but it some times does not happen for a considerable time.? any ideas? does the 4099 signify some overflow?? does it sound like it is inverter noise? might the lower carrier frequency be the fix? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
|
Thank you Keith for mentioning my favourite book on the subject.? As far as I'm concerned there is no better reference on how to deal with noise on anything from PC boards all the way up to entire rooms. John Dammeyer. ? ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Keith Fisk
Sent: March-28-20 1:29 AM
To: [email protected]
Subject: Re: [MachCNC] strange stopping? Hi Spencer Have you tried a proper USB isolator in your USB connection? These range in price from a few dollars for a hobby grade device to around $100 for a proper industrial spec isolator such as the Advantech brand. I can’t recommend what to buy because my setup uses an Ethernet connection to my motion controller so is galvanically isolated by the transformers in the Ethernet ports. I must add that the fundamental physics behind shielding is not well understood and some of that misunderstanding is on display on this thread. Simplistically there are two sources of electromagnetic interference, electrostatic due to voltage and magnetic due to current flow. Electrostatic interference is typically mitigated by earthed screens or shields and in the first instance magnetic interference is mitigated by tightly twisted paired wiring. Cable shielding can also provide protection against magnetic interference but only if it is properly earthed at both ends. At this point arguments generally erupt about the folly of creating an earth loop. Creating a loop is deliberate and provides the mechanism for the magnetic shielding to work. The undesirable magnetic field causes current to flow around the loop which in turn radiates its own magnetic field. The two magnetic fields are in opposite directions and add together giving a resultant tending towards zero.? Rather than attempting to explain this further I would refer group members to a world renowned expert: Henry W Ott and his highly regarded textbook “Noise Reduction Techniques in Electronic Systems” and further, to carefully read installation instructions for VFDs from reputable manufacturers such as ABB, Siemens, Rockwell etc. Good quality VFDs usually have a substantial clamping arrangement for earthing the shield of the motor cable close to the VFD terminals.? The cable shield should also be well earthed to the motor terminal box using a good quality EMC grounding gland. Good quality shielded VFD cable and EMC glands are available from Lapp Kabel and other specialist manufacturers. ? Good luck and regards Keith Fisk.
|
Hi Spencer Have you tried a proper USB isolator in your USB connection? These range in price from a few dollars for a hobby grade device to around $100 for a proper industrial spec isolator such as the Advantech brand. I can’t recommend what to buy because my setup uses an Ethernet connection to my motion controller so is galvanically isolated by the transformers in the Ethernet ports. I must add that the fundamental physics behind shielding is not well understood and some of that misunderstanding is on display on this thread. Simplistically there are two sources of electromagnetic interference, electrostatic due to voltage and magnetic due to current flow. Electrostatic interference is typically mitigated by earthed screens or shields and in the first instance magnetic interference is mitigated by tightly twisted paired wiring. Cable shielding can also provide protection against magnetic interference but only if it is properly earthed at both ends. At this point arguments generally erupt about the folly of creating an earth loop. Creating a loop is deliberate and provides the mechanism for the magnetic shielding to work. The undesirable magnetic field causes current to flow around the loop which in turn radiates its own magnetic field. The two magnetic fields are in opposite directions and add together giving a resultant tending towards zero.? Rather than attempting to explain this further I would refer group members to a world renowned expert: Henry W Ott and his highly regarded textbook “Noise Reduction Techniques in Electronic Systems” and further, to carefully read installation instructions for VFDs from reputable manufacturers such as ABB, Siemens, Rockwell etc. Good quality VFDs usually have a substantial clamping arrangement for earthing the shield of the motor cable close to the VFD terminals.? The cable shield should also be well earthed to the motor terminal box using a good quality EMC grounding gland. Good quality shielded VFD cable and EMC glands are available from Lapp Kabel and other specialist manufacturers. ? Good luck and regards Keith Fisk.
|
Re: strange stopping - dealing with noise issues
wow, what a treatise, much appreciated.
i will ground the motor end of the VFD power cable as well as the VFD end which is now grounded. done
the chassis of the router was not connected to the mains ground before, now it is because of the connection of the motor end of the VFD cable. it is connected now at just that point. the servo drivers seem to have their ground connections not connected to the heat sinks which are attached to the chassis of the router.
so i now have just one ground connection to the chassis and that is to the common ground point through the VFD cable shield/conduit.
is there any reason to connect the chassis elsewhere such as the mains common ground? again it was floating before i connected the VFD cable shield.
i was certain that the PC chassis was not connected to the mains ground because it has a teo wire DC power supply. however the display adapter which goes through a display adapter to VGA adapter and connects to the monitor makes this connection. the monitor has a grounded power supply and apparently the display cable makes this connection. if i remove the cable, the PC chassis is not connected to the mains ground. is there any reason that this could be a problem, should i cut the shield at one end?
i bought one of the cheap USB isolators and it did not work. it might have been that it could not pass enough current to the USB power leads to power the thing i tried to use with it. no data was exchanged if i plugged several things into it. these included the pokeys as well as various things that i did not think would draw much power through the USB. a couple of things did work but they had their own power supplies.
is there a cheap USB isolator that is known to work with the Pokeys? there is one for $90 that has its own isolated power supply and is specifically made for CNC stuff but if a cheap one would work as well i would rather try it.
?
?
Best regards, Spencer Chase 67550 Bell Springs Rd. Garberville, CA 95542 Postal service only. Laytonville, CA 95454 UPS only. Spencer@...Spencer@...Spencer@...(425) 791-0309 (707) 223-8212
toggle quoted message
Show quoted text
------ Original Message ------
Sent: 3/27/2020 10:14:16 PM
Subject: Re: [MachCNC] strange stopping - dealing with noise issues
?
Almost all PCs
with a three prong plug have the DC signal ground connected internally to the AC
mains safety ground. This makes it important to consider the potential for
ground loops. USB signal cables will unavoidably have their?signal ground reference and shield connected to
the AC mains safety ground because of this.
?
You do not need to
provide an external shield over a USB cable in most situations. The data signals
are differential and carried by a twisted pair. Twisted pair differential
signals inherently resist common mode
induced noise which couples into both conductors at about the same amplitude.
Sometimes the induced signal can exceed the "common mode range" of the receiving
device. This is?when a ferrite choke
over the cable can help. PMDX has put a tiny common mode choke on all of our USB
based boards, but even so some host computers suffer from this problem at the
host end of the cable and a choke there can sometimes help.
?
All USB cables
have a shield which may also serve as the negative side of the power delivery
and the signal ground reference. More commonly there is a separate ground wire
to serve as the power and reference connection. Even so, it is common for the
shield of a USB cable to be connected to?signal ground at both ends. This is why I
recommend a redundant larger wire be connected between the computer chassis and
the signal ground at the controller so that most of the current caused by a
ground loop flows through this wire instead of the shield.
?
It is possible to
defeat ground loops by the use?od USB
isolators or to design USB interfaces that are electrically isolated (example
the PMDX-424 SmartBOB), though this is not common because USB was originally
intended for human interface devices such as keyboards and mice that do not
suffer from ground loops. USB isolators can be purchase on eBay for less that
US$20 each. Twisted pair Ethernet also provides ground loop isolation because
the signals are?usually
transformer?coupled.
?
The PMDX-126 is
designed to allow isolation between the PCs logic (DC) ground and the machine
frame ground. Success of this isolation requires proper attention to ground
points and avoiding things such as encoders whose body connects their signal
ground to the machine frame.
?
Coaxial shielding
of a cable protects only against electrostatic fields. It does nothing to block
magnetic fields. That requires a magnetically permable material such as iron,
nickle, ferrite, or mu-metal. Mu-metal alternates layers of copper and nickle
and has properties that shield both electrostatic and magnetic fields. Nice as
this sounds, it is not very flexible mechanically and it tends to empty your
wallet quickly.? 8-)
?
Electrostatic
shielding is provided by a coaxial shield that is grounded at either end or both
ends.?For signal cables, grounding at
only the end that is receiving the signal is preferred.
?
Grounding both
ends of a coaxial shield that covers signal conductors risks allowing current to
flow through the shield. When this happens, the cable will act as a one turn
transformer and couple the magnetic field generated by the shield current into
the signal conductors.
?
If the cable is
delivering power (stepper motor drive current or spindle motor power) then it is
desirable to ground both ends as there is no worry about corrupting the signals
and the grounding provides safety features.
?
USB, twisted pair
Ethernet, and many encoder signals are differential mode signals which help to
cancel common mode noise induced either electrostatically or magnetically. The
operative word is HELP, not eliminate.
?
Motor drive
current to bipolar stepper motors is essentially differential and this helps
reduce the interferance they generate. If ground loops are a concern, then these
cables, if shielded, should have the shield grounded at the driver end. The best
ground for this purpose is the negative terminal of the power source feeding the
stepper drivers.
?
Power cables
between a VFD and a spindle motor are a potent generator of noise due to the
high voltages, and fast rise time of the PWM modulation of the simulated sine
waves generated by the VFD. Ferrite chokes and/or "reactors" can be used to
reduce the noise level somewhat. Because this is a power cable and there is no
signal information to be compromised, you can and should ground the shield at
both ends for safety reasons.
?
As was mentioned
by John D. separation distance is your friend when trying to reduce the amount
of noise induced by one conductor into another. It is also helpful to have noise
generating cables cross signal carrying cables at right angles. Lastly, if
cables are longer than needed, shorten them or fold them in a Z pattern. Coiling
them up results in a better target for noise induced by magnetic
fields.
?
With all of this
being said, sometimes eliminating noise faults is more art than science.
Overthinking and analyzing things does not always trump simply trying things in
the real world.
?
Regards,
Steve
Stallings
PMDX
Electrical
noise can be a bear.? Steve
Spallings mentioned PC grounds and system or motor grounds.? I have his PMDX-126 and unfortunately
the PC I'm using internally somewhere has the DC ground connected to the system
frame which is the third earth prong on the power cord which then connects to
the motor frames through the machine metal. The CUI encoders on the DC servos
serve to further muck things up where their DC ground is connected to the
frame.? Which is of course connected
to the 3 prong and so DC ground earth ground are connected in several places.
?Shielding has no rhyme or reason
here but it's one place where a single ended connection for a shield is a bit
more logical.
?
My EE book on
electrical noise states that the signal grounds should never be connected to the
DC power grounds or frame. ?The
whole point of shielding is that it isolates the two.
?
For your system
also look at magnetic coupling.? The
way a transformer works is a changing magnetic field introduces current in
windings that are also in the magnetic field.? So the spindle motor current flowing
through the wires can generate a field picked up encoder or limit switch wires.
?Short of what is called mu metal
shielding the only solution to electromagnetic interference is distance.? Route them far
apart.
?
Electrostatic
shielding is different.? Twisted
pairs help to null out electric field noise. Shielding can be grounded at one
end or both of the frame (third prong) earth.? The point is you only want the noise
current flowing back through the shield into the frame.? Not through your signal wires which
includes the DC 0V wires.? People
tend to forget what goes out a signal wire is still a signal as it comes back
through what is commonly called the ground or common wire.? (Some manufacturers have called the +5V
to +24V 'common' for limit switches)
?
John
Dammeyer.
?
?
You are trying to fix a wrong
schematic with cosmetic changes. You sure have a ground loop somewhere. Check
your shields, they should be connected one side only with heavy short wire to
good ground. Preferably star connection.
?
i
forgot to mention that, i have ferrites everywhere. that is one of the first
things i do.? i have them on the signal leads to each stepper and even on
the usb cable to the pokeys although the mfg suggested it would not do
anything. i tried a usb signal conditioner thing but it did not work, meaning
that most things plugged into it stopped working.
anyone know of a signal
conditioned for usb that does work?
Best
regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542
Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425)
791-0309
(707) 223-8212
------ Original Message
------
Sent: 3/27/2020 4:03:12
AM
Subject: Re: [MachCNC]
strange stopping
I would probably try
adding ferrite beads to the leads.
I have my router
working really well with the following configuration. Solid state tiny
computer running win 10. Mach 3 latest version Pokeys USB CNC thing
connected to a PDMX.
I am finally getting
smooth motion no lost steps etc etc. Everything works
except.
Occasionally Mach3 just
stops and is totally unresponsive. Can not reset, jog etc. The diag screen
shows all ins and outs off. I have to kill Mach 3 and start
again.
I am pretty sure that
every time it does this, when I restart the 4th axis DRO shows
4099.xxx? the 4th axix is angular.?
I am running a gcode
with a subroutine that repeats over and over with a tool change to allow
inserting a new part for machining. i am also using the subroutine to make
it possible to count parts.?
when this failure
happens is always close to the spindle motor going on or off. it is a
three phase servo run by a high quality US inverter. Forgot the name right
now but it is a good inverter not Chinese no name
stuff.
I am pretty sure the
spindle motor is causing noise that kills the Pokeys. I have proper
grounding and shielding.?
I changed the inverter
carrier frequency from the default of 5Khz to 2khz and have not had the
problem yet but it some times does not happen for a considerable
time.?
any ideas? does the
4099 signify some overflow?? does it sound like it is inverter noise?
might the lower carrier frequency be the fix?
Best
regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542
Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425)
791-0309
(707) 223-8212
|
Re: strange stopping - dealing with noise issues
?
Almost all PCs
with a three prong plug have the DC signal ground connected internally to the AC
mains safety ground. This makes it important to consider the potential for
ground loops. USB signal cables will unavoidably have their?signal ground reference and shield connected to
the AC mains safety ground because of this.
?
You do not need to
provide an external shield over a USB cable in most situations. The data signals
are differential and carried by a twisted pair. Twisted pair differential
signals inherently resist common mode
induced noise which couples into both conductors at about the same amplitude.
Sometimes the induced signal can exceed the "common mode range" of the receiving
device. This is?when a ferrite choke
over the cable can help. PMDX has put a tiny common mode choke on all of our USB
based boards, but even so some host computers suffer from this problem at the
host end of the cable and a choke there can sometimes help.
?
All USB cables
have a shield which may also serve as the negative side of the power delivery
and the signal ground reference. More commonly there is a separate ground wire
to serve as the power and reference connection. Even so, it is common for the
shield of a USB cable to be connected to?signal ground at both ends. This is why I
recommend a redundant larger wire be connected between the computer chassis and
the signal ground at the controller so that most of the current caused by a
ground loop flows through this wire instead of the shield.
?
It is possible to
defeat ground loops by the use?od USB
isolators or to design USB interfaces that are electrically isolated (example
the PMDX-424 SmartBOB), though this is not common because USB was originally
intended for human interface devices such as keyboards and mice that do not
suffer from ground loops. USB isolators can be purchase on eBay for less that
US$20 each. Twisted pair Ethernet also provides ground loop isolation because
the signals are?usually
transformer?coupled.
?
The PMDX-126 is
designed to allow isolation between the PCs logic (DC) ground and the machine
frame ground. Success of this isolation requires proper attention to ground
points and avoiding things such as encoders whose body connects their signal
ground to the machine frame.
?
Coaxial shielding
of a cable protects only against electrostatic fields. It does nothing to block
magnetic fields. That requires a magnetically permable material such as iron,
nickle, ferrite, or mu-metal. Mu-metal alternates layers of copper and nickle
and has properties that shield both electrostatic and magnetic fields. Nice as
this sounds, it is not very flexible mechanically and it tends to empty your
wallet quickly.? 8-)
?
Electrostatic
shielding is provided by a coaxial shield that is grounded at either end or both
ends.?For signal cables, grounding at
only the end that is receiving the signal is preferred.
?
Grounding both
ends of a coaxial shield that covers signal conductors risks allowing current to
flow through the shield. When this happens, the cable will act as a one turn
transformer and couple the magnetic field generated by the shield current into
the signal conductors.
?
If the cable is
delivering power (stepper motor drive current or spindle motor power) then it is
desirable to ground both ends as there is no worry about corrupting the signals
and the grounding provides safety features.
?
USB, twisted pair
Ethernet, and many encoder signals are differential mode signals which help to
cancel common mode noise induced either electrostatically or magnetically. The
operative word is HELP, not eliminate.
?
Motor drive
current to bipolar stepper motors is essentially differential and this helps
reduce the interferance they generate. If ground loops are a concern, then these
cables, if shielded, should have the shield grounded at the driver end. The best
ground for this purpose is the negative terminal of the power source feeding the
stepper drivers.
?
Power cables
between a VFD and a spindle motor are a potent generator of noise due to the
high voltages, and fast rise time of the PWM modulation of the simulated sine
waves generated by the VFD. Ferrite chokes and/or "reactors" can be used to
reduce the noise level somewhat. Because this is a power cable and there is no
signal information to be compromised, you can and should ground the shield at
both ends for safety reasons.
?
As was mentioned
by John D. separation distance is your friend when trying to reduce the amount
of noise induced by one conductor into another. It is also helpful to have noise
generating cables cross signal carrying cables at right angles. Lastly, if
cables are longer than needed, shorten them or fold them in a Z pattern. Coiling
them up results in a better target for noise induced by magnetic
fields.
?
With all of this
being said, sometimes eliminating noise faults is more art than science.
Overthinking and analyzing things does not always trump simply trying things in
the real world.
?
Regards,
Steve
Stallings
PMDX
toggle quoted message
Show quoted text
Electrical
noise can be a bear.? Steve
Spallings mentioned PC grounds and system or motor grounds.? I have his PMDX-126 and unfortunately
the PC I'm using internally somewhere has the DC ground connected to the system
frame which is the third earth prong on the power cord which then connects to
the motor frames through the machine metal. The CUI encoders on the DC servos
serve to further muck things up where their DC ground is connected to the
frame.? Which is of course connected
to the 3 prong and so DC ground earth ground are connected in several places.
?Shielding has no rhyme or reason
here but it's one place where a single ended connection for a shield is a bit
more logical.
?
My EE book on
electrical noise states that the signal grounds should never be connected to the
DC power grounds or frame. ?The
whole point of shielding is that it isolates the two.
?
For your system
also look at magnetic coupling.? The
way a transformer works is a changing magnetic field introduces current in
windings that are also in the magnetic field.? So the spindle motor current flowing
through the wires can generate a field picked up encoder or limit switch wires.
?Short of what is called mu metal
shielding the only solution to electromagnetic interference is distance.? Route them far
apart.
?
Electrostatic
shielding is different.? Twisted
pairs help to null out electric field noise. Shielding can be grounded at one
end or both of the frame (third prong) earth.? The point is you only want the noise
current flowing back through the shield into the frame.? Not through your signal wires which
includes the DC 0V wires.? People
tend to forget what goes out a signal wire is still a signal as it comes back
through what is commonly called the ground or common wire.? (Some manufacturers have called the +5V
to +24V 'common' for limit switches)
?
John
Dammeyer.
?
?
You are trying to fix a wrong
schematic with cosmetic changes. You sure have a ground loop somewhere. Check
your shields, they should be connected one side only with heavy short wire to
good ground. Preferably star connection.
?
i
forgot to mention that, i have ferrites everywhere. that is one of the first
things i do.? i have them on the signal leads to each stepper and even on
the usb cable to the pokeys although the mfg suggested it would not do
anything. i tried a usb signal conditioner thing but it did not work, meaning
that most things plugged into it stopped working.
anyone know of a signal
conditioned for usb that does work?
Best
regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542
Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425)
791-0309
(707) 223-8212
------ Original Message
------
Sent: 3/27/2020 4:03:12
AM
Subject: Re: [MachCNC]
strange stopping
I would probably try
adding ferrite beads to the leads.
I have my router
working really well with the following configuration. Solid state tiny
computer running win 10. Mach 3 latest version Pokeys USB CNC thing
connected to a PDMX.
I am finally getting
smooth motion no lost steps etc etc. Everything works
except.
Occasionally Mach3 just
stops and is totally unresponsive. Can not reset, jog etc. The diag screen
shows all ins and outs off. I have to kill Mach 3 and start
again.
I am pretty sure that
every time it does this, when I restart the 4th axis DRO shows
4099.xxx? the 4th axix is angular.?
I am running a gcode
with a subroutine that repeats over and over with a tool change to allow
inserting a new part for machining. i am also using the subroutine to make
it possible to count parts.?
when this failure
happens is always close to the spindle motor going on or off. it is a
three phase servo run by a high quality US inverter. Forgot the name right
now but it is a good inverter not Chinese no name
stuff.
I am pretty sure the
spindle motor is causing noise that kills the Pokeys. I have proper
grounding and shielding.?
I changed the inverter
carrier frequency from the default of 5Khz to 2khz and have not had the
problem yet but it some times does not happen for a considerable
time.?
any ideas? does the
4099 signify some overflow?? does it sound like it is inverter noise?
might the lower carrier frequency be the fix?
Best
regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542
Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425)
791-0309
(707) 223-8212
|
i always connect shields at one end. i have known this for many years. hopefully my problem was that in an attempt to connect the shield at one end i actually connected it at neither end thinking the connector on the motor contacted the shield. it is insulated by a strain relief bushing made of rubber so there is no contact as i thought there was. now it is grounded at the inverter.?
also hoping that changing the inverter carrier frequency could help. i have it at 2khz now and can go to 1khz.?
since the A DRO goes to limit every time it fails i am pretty sure the Pokeys is getting some noise it can not handle and goes nuts sending a pulses.
?
?
Best regards, Spencer Chase 67550 Bell Springs Rd. Garberville, CA 95542 Postal service only. Laytonville, CA 95454 UPS only. Spencer@...Spencer@...Spencer@...(425) 791-0309 (707) 223-8212
------ Original Message ------
Sent: 3/27/2020 9:32:35 PM
Subject: Re: [MachCNC] strange stopping
a common grounding/shielding mistake often made... you should
only connect your wire shield at one end!
examples: stepper motor being grounded to a metal
chassis...ground at the motor, not at the control box/driver
block.
Control signals that have a ground wire, (V+ power ground, signal
return ground etc, , shield should only be connected at the source
of the signal.
ptegler
On 3/28/2020 12:02 AM, Bertho wrote:
I did not mean to twist your existing
wires.
I was referring to when making harnesses
using individual wires and then twisting the pair.
Bertho
?
?
i think it is all plugged into one
outlet. will double check. not sure how i can twist wires
at this point stuff is pretty mush in place but will look
at the possibility.
Best
regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
------ Original Message ------
Sent: 3/27/2020 4:46:36 PM
Subject: Re: [MachCNC] strange
stopping
A quick addition to John’s good
comments:
Make sure that all AC line cords are
plugged into one wall outlet through a power strip.
Using two different wall outlets can
add a lot of unrelated noise.
?
I am a firm believer in tightly twisted
pair power and signal wires.
It cancels out both electrostatic and
inductive radiated and picked up signals.
Bertho
?
?
?
Electrical
noise can be a bear.? Steve Spallings mentioned PC
grounds and system or motor grounds.? I have his
PMDX-126 and unfortunately the PC I'm using internally
somewhere has the DC ground connected to the system
frame which is the third earth prong on the power cord
which then connects to the motor frames through the
machine metal The CUI encoders on the DC servos serve to
further muck things up where their DC ground is
connected to the frame.? Which is of course connected to
the 3 prong and so DC ground earth ground are connected
in several places.? Shielding has no rhyme or reason
here but it's one place where a single ended connection
for a shield is a bit more logical.
?
My EE
book on electrical noise states that the signal grounds
should never be connected to the DC power grounds or
frame.? The whole point of shielding is that it isolates
the two.
?
For
your system also look at magnetic coupling.? The way a
transformer works is a changing magnetic field
introduces current in windings that are also in the
magnetic field.? So the spindle motor current flowing
through the wires can generate a field picked up encoder
or limit switch wires.? Short of what is called mu metal
shielding the only solution to electromagnetic
interference is distance.? Route them far apart.
?
Electrostatic
shielding is different.? Twisted pairs help to null out
electric field noise. Shielding can be grounded at one
end or both of the frame (third prong) earth.? The point
is you only want the noise current flowing back through
the shield into the frame.? Not through your signal
wires which includes the DC 0V wires.? People tend to
forget what goes out a signal wire is still a signal as
it comes back through what is commonly called the ground
or common wire.? (Some manufacturers have called the +5V
to +24V 'common' for limit switches)
?
John
Dammeyer.
?
?
You are trying to fix a
wrong schematic with cosmetic changes. You sure have a
ground loop somewhere. Check your shields, they should
be connected one side only with heavy short wire to good
ground. Preferably star connection
?
i forgot to
mention that, i have ferrites everywhere. that is
one of the first things i do.? i have them on the
signal leads to each stepper and even on the usb
cable to the pokeys although the mfg suggested it
would not do anything. i tried a usb signal
conditioner thing but it did not work, meaning
that most things plugged into it stopped working.
anyone know of
a signal conditioned for usb that does work?
Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
------
Original Message ------
Sent:
3/27/2020 4:03:12 AM
Subject: Re:
[MachCNC] strange stopping
I would
probably try adding ferrite beads to the leads.
I have
my router working really well with the
following configuration. Solid state tiny
computer running win 10. Mach 3 latest
version Pokeys USB CNC thing connected to
a PDMX.
I am
finally getting smooth motion no lost
steps etc etc. Everything works except.
Occasionally
Mach3 just stops and is totally
unresponsive. Can not reset, jog etc. The
diag screen shows all ins and outs off. I
have to kill Mach 3 and start again.
I am
pretty sure that every time it does this,
when I restart the 4th axis DRO shows
4099.xxx? the 4th axix is angular?
I am
running a gcode with a subroutine that
repeats over and over with a tool change
to allow inserting a new part for
machining. i am also using the subroutine
to make it possible to count parts.?
when
this failure happens is always close to
the spindle motor going on or off. it is a
three phase servo run by a high quality US
inverter. Forgot the name right now but it
is a good inverter not Chinese no name
stuff.
I am
pretty sure the spindle motor is causing
noise that kills the Pokeys. I have proper
grounding and shielding.?
I
changed the inverter carrier frequency
from the default of 5Khz to 2khz and have
not had the problem yet but it some times
does not happen for a considerable time.?
any
ideas? does the 4099 signify some
overflow?? does it sound like it is
inverter noise? might the lower carrier
frequency be the fix?
Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service
only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@mcnorg
(425) 791-0309
(707) 223-8212
--
Paul Tegler
ptegler@...
|
yes, i know i was talking about harnesses that are already made and taking them apart and twisting the wires.?
however i am almost certain that the problem is not in the signal wires to the motors etc. all of that is properly grounded and there was never a problem before the Pokeys USB thing. whatever noise is getting in is through the USB, almost certainly. since the shield for the spindle motor power was not grounded at either end, i am hopeful that grounding it at the inverter will fix the problem. otherwise i need to deal with the usb cable or get some sort of isolator.?
or just ditch the Pokeys and get a network device.
recommendations?>
?
?
Best regards, Spencer Chase 67550 Bell Springs Rd. Garberville, CA 95542 Postal service only. Laytonville, CA 95454 UPS only. Spencer@...Spencer@...Spencer@...(425) 791-0309 (707) 223-8212
------ Original Message ------
Sent: 3/27/2020 9:02:28 PM
Subject: Re: [MachCNC] strange stopping
I did not mean to twist your existing wires. I was referring to when making harnesses using individual wires and then twisting the pair. Bertho ? ? i think it is all plugged into one outlet. will double check. not sure how i can twist wires at this point stuff is pretty mush in place but will look at the possibility. Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212 ------ Original Message ------ Sent: 3/27/2020 4:46:36 PM Subject: Re: [MachCNC] strange stopping A quick addition to John’s good comments: Make sure that all AC line cords are plugged into one wall outlet through a power strip. Using two different wall outlets can add a lot of unrelated noise. ? I am a firm believer in tightly twisted pair power and signal wires. It cancels out both electrostatic and inductive radiated and picked up signals. Bertho ? ? ? Electrical noise can be a bear.? Steve Spallings mentioned PC grounds and system or motor grounds.? I have his PMDX-126 and unfortunately the PC I'm using internally somewhere has the DC ground connected to the system frame which is the third earth prong on the power cord which then connects to the motor frames through the machine metal. The CUI encoders on the DC servos serve to further muck things up where their DC ground is connected to the frame.? Which is of course connected to the 3 prong and so DC ground earth ground are connected in several places.? Shielding has no rhyme or reason here but it's one place where a single ended connection for a shield is a bit more logical. ? My EE book on electrical noise states that the signal grounds should never be connected to the DC power grounds or frame.? The whole point of shielding is that it isolates the two. ? For your system also look at magnetic coupling.? The way a transformer works is a changing magnetic field introduces current in windings that are also in the magnetic field.? So the spindle motor current flowing through the wires can generate a field picked up encoder or limit switch wires.? Short of what is called mu metal shielding the only solution to electromagnetic interference is distance.? Route them far apart. ? Electrostatic shielding is different.? Twisted pairs help to null out electric field noise. Shielding can be grounded at one end or both of the frame (third prong) earth.? The point is you only want the noise current flowing back through the shield into the frame.? Not through your signal wires which includes the DC 0V wires.? People tend to forget what goes out a signal wire is still a signal as it comes back through what is commonly called the ground or common wire.? (Some manufacturers have called the +5V to +24V 'common' for limit switches) ? John Dammeyer. ? ? You are trying to fix a wrong schematic with cosmetic changes. You sure have a ground loop somewhere. Check your shields, they should be connected one side only with heavy short wire to good ground. Preferably star connection. ? i forgot to mention that, i have ferrites everywhere. that is one of the first things i do.? i have them on the signal leads to each stepper and even on the usb cable to the pokeys although the mfg suggested it would not do anything. i tried a usb signal conditioner thing but it did not work, meaning that most things plugged into it stopped working. anyone know of a signal conditioned for usb that does work? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212 ------ Original Message ------ Sent: 3/27/2020 4:03:12 AM Subject: Re: [MachCNC] strange stopping I would probably try adding ferrite beads to the leads. I have my router working really well with the following configuration. Solid state tiny computer running win 10. Mach 3 latest version Pokeys USB CNC thing connected to a PDMX. I am finally getting smooth motion no lost steps etc etc. Everything works except. Occasionally Mach3 just stops and is totally unresponsive. Can not reset, jog etc. The diag screen shows all ins and outs off. I have to kill Mach 3 and start again. I am pretty sure that every time it does this, when I restart the 4th axis DRO shows 4099.xxx? the 4th axix is angular.? I am running a gcode with a subroutine that repeats over and over with a tool change to allow inserting a new part for machining. i am also using the subroutine to make it possible to count parts.? when this failure happens is always close to the spindle motor going on or off. it is a three phase servo run by a high quality US inverter. Forgot the name right now but it is a good inverter not Chinese no name stuff. I am pretty sure the spindle motor is causing noise that kills the Pokeys. I have proper grounding and shielding.? I changed the inverter carrier frequency from the default of 5Khz to 2khz and have not had the problem yet but it some times does not happen for a considerable time.? any ideas? does the 4099 signify some overflow?? does it sound like it is inverter noise? might the lower carrier frequency be the fix? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
|
a common grounding/shielding mistake often made... you should
only connect your wire shield at one end!
examples: stepper motor being grounded to a metal
chassis...ground at the motor, not at the control box/driver
block.
Control signals that have a ground wire, (V+ power ground, signal
return ground etc, , shield should only be connected at the source
of the signal.
ptegler
On 3/28/2020 12:02 AM, Bertho wrote:
I did not mean to twist your existing
wires.
I was referring to when making harnesses
using individual wires and then twisting the pair.
Bertho
?
?
i think it is all plugged into one
outlet. will double check. not sure how i can twist wires
at this point stuff is pretty mush in place but will look
at the possibility.
Best
regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
------ Original Message ------
Sent: 3/27/2020 4:46:36 PM
Subject: Re: [MachCNC] strange
stopping
A quick addition to John’s good
comments:
Make sure that all AC line cords are
plugged into one wall outlet through a power strip.
Using two different wall outlets can
add a lot of unrelated noise.
?
I am a firm believer in tightly twisted
pair power and signal wires.
It cancels out both electrostatic and
inductive radiated and picked up signals.
Bertho
?
?
?
Electrical
noise can be a bear.? Steve Spallings mentioned PC
grounds and system or motor grounds.? I have his
PMDX-126 and unfortunately the PC I'm using internally
somewhere has the DC ground connected to the system
frame which is the third earth prong on the power cord
which then connects to the motor frames through the
machine metal The CUI encoders on the DC servos serve to
further muck things up where their DC ground is
connected to the frame.? Which is of course connected to
the 3 prong and so DC ground earth ground are connected
in several places.? Shielding has no rhyme or reason
here but it's one place where a single ended connection
for a shield is a bit more logical.
?
My EE
book on electrical noise states that the signal grounds
should never be connected to the DC power grounds or
frame.? The whole point of shielding is that it isolates
the two.
?
For
your system also look at magnetic coupling.? The way a
transformer works is a changing magnetic field
introduces current in windings that are also in the
magnetic field.? So the spindle motor current flowing
through the wires can generate a field picked up encoder
or limit switch wires.? Short of what is called mu metal
shielding the only solution to electromagnetic
interference is distance.? Route them far apart.
?
Electrostatic
shielding is different.? Twisted pairs help to null out
electric field noise. Shielding can be grounded at one
end or both of the frame (third prong) earth.? The point
is you only want the noise current flowing back through
the shield into the frame.? Not through your signal
wires which includes the DC 0V wires.? People tend to
forget what goes out a signal wire is still a signal as
it comes back through what is commonly called the ground
or common wire.? (Some manufacturers have called the +5V
to +24V 'common' for limit switches)
?
John
Dammeyer.
?
?
You are trying to fix a
wrong schematic with cosmetic changes. You sure have a
ground loop somewhere. Check your shields, they should
be connected one side only with heavy short wire to good
ground. Preferably star connection
?
i forgot to
mention that, i have ferrites everywhere. that is
one of the first things i do.? i have them on the
signal leads to each stepper and even on the usb
cable to the pokeys although the mfg suggested it
would not do anything. i tried a usb signal
conditioner thing but it did not work, meaning
that most things plugged into it stopped working.
anyone know of
a signal conditioned for usb that does work?
Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
------
Original Message ------
Sent:
3/27/2020 4:03:12 AM
Subject: Re:
[MachCNC] strange stopping
I would
probably try adding ferrite beads to the leads.
I have
my router working really well with the
following configuration. Solid state tiny
computer running win 10. Mach 3 latest
version Pokeys USB CNC thing connected to
a PDMX.
I am
finally getting smooth motion no lost
steps etc etc. Everything works except.
Occasionally
Mach3 just stops and is totally
unresponsive. Can not reset, jog etc. The
diag screen shows all ins and outs off. I
have to kill Mach 3 and start again.
I am
pretty sure that every time it does this,
when I restart the 4th axis DRO shows
4099.xxx? the 4th axix is angular?
I am
running a gcode with a subroutine that
repeats over and over with a tool change
to allow inserting a new part for
machining. i am also using the subroutine
to make it possible to count parts.?
when
this failure happens is always close to
the spindle motor going on or off. it is a
three phase servo run by a high quality US
inverter. Forgot the name right now but it
is a good inverter not Chinese no name
stuff.
I am
pretty sure the spindle motor is causing
noise that kills the Pokeys. I have proper
grounding and shielding.?
I
changed the inverter carrier frequency
from the default of 5Khz to 2khz and have
not had the problem yet but it some times
does not happen for a considerable time.?
any
ideas? does the 4099 signify some
overflow?? does it sound like it is
inverter noise? might the lower carrier
frequency be the fix?
Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service
only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@mcnorg
(425) 791-0309
(707) 223-8212
--
Paul Tegler
ptegler@...
|
I did not mean to twist your existing wires. I was referring to when making harnesses using individual wires and then twisting the pair. Bertho ?
toggle quoted message
Show quoted text
From: [email protected] < [email protected]> On Behalf Of spencer@... Sent: Friday, March 27, 2020 23:43 To: [email protected]Subject: Re: [MachCNC] strange stopping ? i think it is all plugged into one outlet. will double check. not sure how i can twist wires at this point stuff is pretty mush in place but will look at the possibility. Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212 ------ Original Message ------ Sent: 3/27/2020 4:46:36 PM Subject: Re: [MachCNC] strange stopping A quick addition to John’s good comments: Make sure that all AC line cords are plugged into one wall outlet through a power strip. Using two different wall outlets can add a lot of unrelated noise. ? I am a firm believer in tightly twisted pair power and signal wires. It cancels out both electrostatic and inductive radiated and picked up signals. Bertho ? ? ? Electrical noise can be a bear.? Steve Spallings mentioned PC grounds and system or motor grounds.? I have his PMDX-126 and unfortunately the PC I'm using internally somewhere has the DC ground connected to the system frame which is the third earth prong on the power cord which then connects to the motor frames through the machine metal. The CUI encoders on the DC servos serve to further muck things up where their DC ground is connected to the frame.? Which is of course connected to the 3 prong and so DC ground earth ground are connected in several places.? Shielding has no rhyme or reason here but it's one place where a single ended connection for a shield is a bit more logical. ? My EE book on electrical noise states that the signal grounds should never be connected to the DC power grounds or frame.? The whole point of shielding is that it isolates the two. ? For your system also look at magnetic coupling.? The way a transformer works is a changing magnetic field introduces current in windings that are also in the magnetic field.? So the spindle motor current flowing through the wires can generate a field picked up encoder or limit switch wires.? Short of what is called mu metal shielding the only solution to electromagnetic interference is distance.? Route them far apart. ? Electrostatic shielding is different.? Twisted pairs help to null out electric field noise. Shielding can be grounded at one end or both of the frame (third prong) earth.? The point is you only want the noise current flowing back through the shield into the frame.? Not through your signal wires which includes the DC 0V wires.? People tend to forget what goes out a signal wire is still a signal as it comes back through what is commonly called the ground or common wire.? (Some manufacturers have called the +5V to +24V 'common' for limit switches) ? John Dammeyer. ? ? You are trying to fix a wrong schematic with cosmetic changes. You sure have a ground loop somewhere. Check your shields, they should be connected one side only with heavy short wire to good ground. Preferably star connection. ? i forgot to mention that, i have ferrites everywhere. that is one of the first things i do.? i have them on the signal leads to each stepper and even on the usb cable to the pokeys although the mfg suggested it would not do anything. i tried a usb signal conditioner thing but it did not work, meaning that most things plugged into it stopped working. anyone know of a signal conditioned for usb that does work? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212 ------ Original Message ------ Sent: 3/27/2020 4:03:12 AM Subject: Re: [MachCNC] strange stopping I would probably try adding ferrite beads to the leads. I have my router working really well with the following configuration. Solid state tiny computer running win 10. Mach 3 latest version Pokeys USB CNC thing connected to a PDMX. I am finally getting smooth motion no lost steps etc etc. Everything works except. Occasionally Mach3 just stops and is totally unresponsive. Can not reset, jog etc. The diag screen shows all ins and outs off. I have to kill Mach 3 and start again. I am pretty sure that every time it does this, when I restart the 4th axis DRO shows 4099.xxx? the 4th axix is angular.? I am running a gcode with a subroutine that repeats over and over with a tool change to allow inserting a new part for machining. i am also using the subroutine to make it possible to count parts.? when this failure happens is always close to the spindle motor going on or off. it is a three phase servo run by a high quality US inverter. Forgot the name right now but it is a good inverter not Chinese no name stuff. I am pretty sure the spindle motor is causing noise that kills the Pokeys. I have proper grounding and shielding.? I changed the inverter carrier frequency from the default of 5Khz to 2khz and have not had the problem yet but it some times does not happen for a considerable time.? any ideas? does the 4099 signify some overflow?? does it sound like it is inverter noise? might the lower carrier frequency be the fix? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
|
it doesn't fail at the same point every time. there are actually two points in the code where it fails. one is definitely after the spindle starts on a new run. the program begins with a spindle on and the spindle goes on and then it locks up.?
the other is a short time after the spindle goes off but i am less sure about that exact location.
when i restart mach3 the A axis DRO always reads 4009.something or other. i think that noise is killing the pokeys which responds by sending a shit load of a pulses which overruns the a limit and this is what kills mach3 if the limit were higher it would probably just take a few ms longer while the pokeys is going nuts. never had this problem in 7 years making many thousands of parts. other problems but never this. it only started with the usb pokeys.
i grounded my spindle motor shield, who knows.
?
?
Best regards, Spencer Chase 67550 Bell Springs Rd. Garberville, CA 95542 Postal service only. Laytonville, CA 95454 UPS only. Spencer@...Spencer@...Spencer@...(425) 791-0309 (707) 223-8212
------ Original Message ------
Sent: 3/27/2020 8:22:20 PM
Subject: Re: [MachCNC] strange stopping
Spencer
?
First, your comment about the A stopping
at the same value each? time. I seem to remember from a few years back that
there was a bit of a discussion about the A having a move limit in Mach 3. ?Don’t
remember the detials
?
Second , a noise issue seldom, if? ever,
fails at exactly the same point every time. I kind of? doubt that this is your
problem.
?
On the second ?point though I had issues when
I switched PCs a few years back. ?Chased ?noise ?issues for a few weeks until I
discovered my PC LPPT port was a 3.5vdc port vs a 5 vdc one, very common on later
PC’s. (I didn’t discover that but was pointed to check that by the group) .That
voltage would allow “ANY” noise in. ?A later BOB that would handle the 3.5vdc signals
solved that issue.
?
Don
?
.?
?
?
one more thing. i never had this problem until i
switched to the Pokeys from the parallel port. so i am pretty sure that the
noise is getting into the Pokeys through the USB cable.?
so should i put a braid over the USB cable or try to
find a better shielded version and connect the ground only at the BOB ground
which is common to everything else.?
my computer does not have a three wire power supply. it
has "desktop" wall wart supply. i have no idea where the PC grounds
are connected or if the chassis is connected to anything.
Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542
Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
------ Original Message ------
Sent: 3/27/2020 3:58:44 PM
Subject: Re: [MachCNC] strange stopping
Electrical noise can be a bear.? Steve
Spallings mentioned PC grounds and system or motor grounds.? I have his
PMDX-126 and unfortunately the PC I'm using internally somewhere has the DC
ground connected to the system frame which is the third earth prong on the
power cord which then connects to the motor frames through the machine metal.
The CUI encoders on the DC servos serve to further muck things up where their
DC ground is connected to the frame.? Which is of course connected to the 3
prong and so DC ground earth ground are connected in several places.? Shielding
has no rhyme or reason here but it's one place where a single ended connection
for a shield is a bit more logical.
?
My EE book on electrical noise states
that the signal grounds should never be connected to the DC power grounds or
frame.? The whole point of shielding is that it isolates the two.
?
For your system also look at magnetic
coupling.? The way a transformer works is a changing magnetic field introduces
current in windings that are also in the magnetic field.? So the spindle motor
current flowing through the wires can generate a field picked up encoder or
limit switch wires.? Short of what is called mu metal shielding the only
solution to electromagnetic interference is distance.? Route them far apart.
?
Electrostatic shielding is different.?
Twisted pairs help to null out electric field noise. Shielding can be grounded
at one end or both of the frame (third prong) earth.? The point is you only
want the noise current flowing back through the shield into the frame.? Not
through your signal wires which includes the DC 0V wires.? People tend to
forget what goes out a signal wire is still a signal as it comes back through
what is commonly called the ground or common wire.? (Some manufacturers have
called the +5V to +24V 'common' for limit switches)
?
John Dammeyer.
?
?
You are trying to fix a
wrong schematic with cosmetic changes. You sure have a ground loop somewhere.
Check your shields, they should be connected one side only with heavy short
wire to good ground. Preferably star connection.
?
i forgot to mention that, i have ferrites everywhere. that is one of
the first things i do.? i have them on the signal leads to each stepper
and even on the usb cable to the pokeys although the mfg suggested it would not
do anything. i tried a usb signal conditioner thing but it did not work,
meaning that most things plugged into it stopped working.
anyone know of a signal conditioned for usb that does work?
Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542
Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
------ Original Message ------
Sent: 3/27/2020 4:03:12 AM
Subject: Re: [MachCNC] strange stopping
I would probably try
adding ferrite beads to the leads.
I have my router working really well with the following configuration.
Solid state tiny computer running win 10. Mach 3 latest version Pokeys USB CNC
thing connected to a PDMX.
I am finally getting smooth motion no lost steps etc etc. Everything
works except.
Occasionally Mach3 just stops and is totally unresponsive. Can not
reset, jog etc. The diag screen shows all ins and outs off. I have to kill Mach
3 and start again.
I am pretty sure that every time it does this, when I restart the 4th
axis DRO shows 4099.xxx? the 4th axix is angular.?
I am running a gcode with a subroutine that repeats over and over with
a tool change to allow inserting a new part for machining. i am also using the
subroutine to make it possible to count parts.?
when this failure happens is always close to the spindle motor going on
or off. it is a three phase servo run by a high quality US inverter.
Forgot the name right now but it is a good inverter not Chinese no name stuff.
I am pretty sure the spindle motor is causing noise that kills the
Pokeys. I have proper grounding and shielding.?
I changed the inverter carrier frequency from the default of 5Khz to
2khz and have not had the problem yet but it some times does not happen for a
considerable time.?
any ideas? does the 4099 signify some overflow?? does it sound
like it is inverter noise? might the lower carrier frequency be the fix?
Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542
Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
|
i have read a lot online about usb noise and it seems to be a problem in lots of places. unfortunate that it is so ubiquitous but so fucked up, sort of like bluetooth.
does anyone think that the expensive usb isolators do anything? i am about to switch to ethernet.?
are there twisted signal wire usb cables??
does providing a separate 5 volt tupply to the pokeys help?
what network device is recommended? i would like to keep the PDMX as it is all wired and has worked perfectly for years. i also have about three backups.
?
?
Best regards, Spencer Chase 67550 Bell Springs Rd. Garberville, CA 95542 Postal service only. Laytonville, CA 95454 UPS only. Spencer@...Spencer@...Spencer@...(425) 791-0309 (707) 223-8212
------ Original Message ------
Sent: 3/27/2020 2:56:35 PM
Subject: Re: [MachCNC] strange stopping
I had a lot of noise problems with my Mach 4 and a Pokeys controller using the USB interface.? My wiring was carefully done. I removed the USB cable and switched to ethernet and I have not had a problem since that time. Bertho ? ? i forgot to mention that, i have ferrites everywhere. that is one of the first things i do.? i have them on the signal leads to each stepper and even on the usb cable to the pokeys although the mfg suggested it would not do anything. i tried a usb signal conditioner thing but it did not work, meaning that most things plugged into it stopped working. anyone know of a signal conditioned for usb that does work? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212 ------ Original Message ------ Sent: 3/27/2020 4:03:12 AM Subject: Re: [MachCNC] strange stopping I would probably try adding ferrite beads to the leads. I have my router working really well with the following configuration. Solid state tiny computer running win 10. Mach 3 latest version Pokeys USB CNC thing connected to a PDMX. I am finally getting smooth motion no lost steps etc etc. Everything works except. Occasionally Mach3 just stops and is totally unresponsive. Can not reset, jog etc. The diag screen shows all ins and outs off. I have to kill Mach 3 and start again. I am pretty sure that every time it does this, when I restart the 4th axis DRO shows 4099.xxx? the 4th axix is angular.? I am running a gcode with a subroutine that repeats over and over with a tool change to allow inserting a new part for machining. i am also using the subroutine to make it possible to count parts.? when this failure happens is always close to the spindle motor going on or off. it is a three phase servo run by a high quality US inverter. Forgot the name right now but it is a good inverter not Chinese no name stuff. I am pretty sure the spindle motor is causing noise that kills the Pokeys. I have proper grounding and shielding.? I changed the inverter carrier frequency from the default of 5Khz to 2khz and have not had the problem yet but it some times does not happen for a considerable time.? any ideas? does the 4099 signify some overflow?? does it sound like it is inverter noise? might the lower carrier frequency be the fix? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
|
i think it is all plugged into one outlet. will double check. not sure how i can twist wires at this point stuff is pretty mush in place but will look at the possibility.
?
?
Best regards, Spencer Chase 67550 Bell Springs Rd. Garberville, CA 95542 Postal service only. Laytonville, CA 95454 UPS only. Spencer@...Spencer@...Spencer@...(425) 791-0309 (707) 223-8212
------ Original Message ------
Sent: 3/27/2020 4:46:36 PM
Subject: Re: [MachCNC] strange stopping
A quick addition to John’s good comments: Make sure that all AC line cords are plugged into one wall outlet through a power strip. Using two different wall outlets can add a lot of unrelated noise. ? I am a firm believer in tightly twisted pair power and signal wires. It cancels out both electrostatic and inductive radiated and picked up signals. Bertho ? ? ? Electrical noise can be a bear.? Steve Spallings mentioned PC grounds and system or motor grounds.? I have his PMDX-126 and unfortunately the PC I'm using internally somewhere has the DC ground connected to the system frame which is the third earth prong on the power cord which then connects to the motor frames through the machine metal. The CUI encoders on the DC servos serve to further muck things up where their DC ground is connected to the frame.? Which is of course connected to the 3 prong and so DC ground earth ground are connected in several places.? Shielding has no rhyme or reason here but it's one place where a single ended connection for a shield is a bit more logical. ? My EE book on electrical noise states that the signal grounds should never be connected to the DC power grounds or frame.? The whole point of shielding is that it isolates the two. ? For your system also look at magnetic coupling.? The way a transformer works is a changing magnetic field introduces current in windings that are also in the magnetic field.? So the spindle motor current flowing through the wires can generate a field picked up encoder or limit switch wires.? Short of what is called mu metal shielding the only solution to electromagnetic interference is distance.? Route them far apart. ? Electrostatic shielding is different.? Twisted pairs help to null out electric field noise. Shielding can be grounded at one end or both of the frame (third prong) earth.? The point is you only want the noise current flowing back through the shield into the frame.? Not through your signal wires which includes the DC 0V wires.? People tend to forget what goes out a signal wire is still a signal as it comes back through what is commonly called the ground or common wire.? (Some manufacturers have called the +5V to +24V 'common' for limit switches) ? John Dammeyer. ? ? You are trying to fix a wrong schematic with cosmetic changes. You sure have a ground loop somewhere. Check your shields, they should be connected one side only with heavy short wire to good ground. Preferably star connection. ? i forgot to mention that, i have ferrites everywhere. that is one of the first things i do.? i have them on the signal leads to each stepper and even on the usb cable to the pokeys although the mfg suggested it would not do anything. i tried a usb signal conditioner thing but it did not work, meaning that most things plugged into it stopped working. anyone know of a signal conditioned for usb that does work? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212 ------ Original Message ------ Sent: 3/27/2020 4:03:12 AM Subject: Re: [MachCNC] strange stopping I would probably try adding ferrite beads to the leads. I have my router working really well with the following configuration. Solid state tiny computer running win 10. Mach 3 latest version Pokeys USB CNC thing connected to a PDMX. I am finally getting smooth motion no lost steps etc etc. Everything works except. Occasionally Mach3 just stops and is totally unresponsive. Can not reset, jog etc. The diag screen shows all ins and outs off. I have to kill Mach 3 and start again. I am pretty sure that every time it does this, when I restart the 4th axis DRO shows 4099.xxx? the 4th axix is angular.? I am running a gcode with a subroutine that repeats over and over with a tool change to allow inserting a new part for machining. i am also using the subroutine to make it possible to count parts.? when this failure happens is always close to the spindle motor going on or off. it is a three phase servo run by a high quality US inverter. Forgot the name right now but it is a good inverter not Chinese no name stuff. I am pretty sure the spindle motor is causing noise that kills the Pokeys. I have proper grounding and shielding.? I changed the inverter carrier frequency from the default of 5Khz to 2khz and have not had the problem yet but it some times does not happen for a considerable time.? any ideas? does the 4099 signify some overflow?? does it sound like it is inverter noise? might the lower carrier frequency be the fix? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
|
Spencer
?
First, your comment about the A stopping
at the same value each? time. I seem to remember from a few years back that
there was a bit of a discussion about the A having a move limit in Mach 3. ?Don’t
remember the detials
?
Second , a noise issue seldom, if? ever,
fails at exactly the same point every time. I kind of? doubt that this is your
problem.
?
On the second ?point though I had issues when
I switched PCs a few years back. ?Chased ?noise ?issues for a few weeks until I
discovered my PC LPPT port was a 3.5vdc port vs a 5 vdc one, very common on later
PC’s. (I didn’t discover that but was pointed to check that by the group) .That
voltage would allow “ANY” noise in. ?A later BOB that would handle the 3.5vdc signals
solved that issue.
?
Don
?
.?
?
?
one more thing. i never had this problem until i
switched to the Pokeys from the parallel port. so i am pretty sure that the
noise is getting into the Pokeys through the USB cable.?
so should i put a braid over the USB cable or try to
find a better shielded version and connect the ground only at the BOB ground
which is common to everything else.?
my computer does not have a three wire power supply. it
has "desktop" wall wart supply. i have no idea where the PC grounds
are connected or if the chassis is connected to anything.
Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542
Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
toggle quoted message
Show quoted text
------ Original Message ------
Sent: 3/27/2020 3:58:44 PM
Subject: Re: [MachCNC] strange stopping
Electrical noise can be a bear.? Steve
Spallings mentioned PC grounds and system or motor grounds.? I have his
PMDX-126 and unfortunately the PC I'm using internally somewhere has the DC
ground connected to the system frame which is the third earth prong on the
power cord which then connects to the motor frames through the machine metal.
The CUI encoders on the DC servos serve to further muck things up where their
DC ground is connected to the frame.? Which is of course connected to the 3
prong and so DC ground earth ground are connected in several places.? Shielding
has no rhyme or reason here but it's one place where a single ended connection
for a shield is a bit more logical.
?
My EE book on electrical noise states
that the signal grounds should never be connected to the DC power grounds or
frame.? The whole point of shielding is that it isolates the two.
?
For your system also look at magnetic
coupling.? The way a transformer works is a changing magnetic field introduces
current in windings that are also in the magnetic field.? So the spindle motor
current flowing through the wires can generate a field picked up encoder or
limit switch wires.? Short of what is called mu metal shielding the only
solution to electromagnetic interference is distance.? Route them far apart.
?
Electrostatic shielding is different.?
Twisted pairs help to null out electric field noise. Shielding can be grounded
at one end or both of the frame (third prong) earth.? The point is you only
want the noise current flowing back through the shield into the frame.? Not
through your signal wires which includes the DC 0V wires.? People tend to
forget what goes out a signal wire is still a signal as it comes back through
what is commonly called the ground or common wire.? (Some manufacturers have
called the +5V to +24V 'common' for limit switches)
?
John Dammeyer.
?
?
You are trying to fix a
wrong schematic with cosmetic changes. You sure have a ground loop somewhere.
Check your shields, they should be connected one side only with heavy short
wire to good ground. Preferably star connection.
?
i forgot to mention that, i have ferrites everywhere. that is one of
the first things i do.? i have them on the signal leads to each stepper
and even on the usb cable to the pokeys although the mfg suggested it would not
do anything. i tried a usb signal conditioner thing but it did not work,
meaning that most things plugged into it stopped working.
anyone know of a signal conditioned for usb that does work?
Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542
Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
------ Original Message ------
Sent: 3/27/2020 4:03:12 AM
Subject: Re: [MachCNC] strange stopping
I would probably try
adding ferrite beads to the leads.
I have my router working really well with the following configuration.
Solid state tiny computer running win 10. Mach 3 latest version Pokeys USB CNC
thing connected to a PDMX.
I am finally getting smooth motion no lost steps etc etc. Everything
works except.
Occasionally Mach3 just stops and is totally unresponsive. Can not
reset, jog etc. The diag screen shows all ins and outs off. I have to kill Mach
3 and start again.
I am pretty sure that every time it does this, when I restart the 4th
axis DRO shows 4099.xxx? the 4th axix is angular.?
I am running a gcode with a subroutine that repeats over and over with
a tool change to allow inserting a new part for machining. i am also using the
subroutine to make it possible to count parts.?
when this failure happens is always close to the spindle motor going on
or off. it is a three phase servo run by a high quality US inverter.
Forgot the name right now but it is a good inverter not Chinese no name stuff.
I am pretty sure the spindle motor is causing noise that kills the
Pokeys. I have proper grounding and shielding.?
I changed the inverter carrier frequency from the default of 5Khz to
2khz and have not had the problem yet but it some times does not happen for a
considerable time.?
any ideas? does the 4099 signify some overflow?? does it sound
like it is inverter noise? might the lower carrier frequency be the fix?
Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542
Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
|
A quick addition to John’s good comments: Make sure that all AC line cords are plugged into one wall outlet through a power strip. Using two different wall outlets can add a lot of unrelated noise. ? I am a firm believer in tightly twisted pair power and signal wires. It cancels out both electrostatic and inductive radiated and picked up signals. Bertho ? ?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]> On Behalf Of John Dammeyer
Sent: Friday, March 27, 2020 18:59
To: [email protected]
Subject: Re: [MachCNC] strange stopping? Electrical noise can be a bear.? Steve Spallings mentioned PC grounds and system or motor grounds.? I have his PMDX-126 and unfortunately the PC I'm using internally somewhere has the DC ground connected to the system frame which is the third earth prong on the power cord which then connects to the motor frames through the machine metal. The CUI encoders on the DC servos serve to further muck things up where their DC ground is connected to the frame.? Which is of course connected to the 3 prong and so DC ground earth ground are connected in several places.? Shielding has no rhyme or reason here but it's one place where a single ended connection for a shield is a bit more logical. ? My EE book on electrical noise states that the signal grounds should never be connected to the DC power grounds or frame.? The whole point of shielding is that it isolates the two. ? For your system also look at magnetic coupling.? The way a transformer works is a changing magnetic field introduces current in windings that are also in the magnetic field.? So the spindle motor current flowing through the wires can generate a field picked up encoder or limit switch wires.? Short of what is called mu metal shielding the only solution to electromagnetic interference is distance.? Route them far apart. ? Electrostatic shielding is different.? Twisted pairs help to null out electric field noise. Shielding can be grounded at one end or both of the frame (third prong) earth.? The point is you only want the noise current flowing back through the shield into the frame.? Not through your signal wires which includes the DC 0V wires.? People tend to forget what goes out a signal wire is still a signal as it comes back through what is commonly called the ground or common wire.? (Some manufacturers have called the +5V to +24V 'common' for limit switches) ? John Dammeyer. ? ? You are trying to fix a wrong schematic with cosmetic changes. You sure have a ground loop somewhere. Check your shields, they should be connected one side only with heavy short wire to good ground. Preferably star connection. ? i forgot to mention that, i have ferrites everywhere. that is one of the first things i do.? i have them on the signal leads to each stepper and even on the usb cable to the pokeys although the mfg suggested it would not do anything. i tried a usb signal conditioner thing but it did not work, meaning that most things plugged into it stopped working. anyone know of a signal conditioned for usb that does work? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212 ------ Original Message ------ Sent: 3/27/2020 4:03:12 AM Subject: Re: [MachCNC] strange stopping I would probably try adding ferrite beads to the leads. I have my router working really well with the following configuration. Solid state tiny computer running win 10. Mach 3 latest version Pokeys USB CNC thing connected to a PDMX. I am finally getting smooth motion no lost steps etc etc. Everything works except. Occasionally Mach3 just stops and is totally unresponsive. Can not reset, jog etc. The diag screen shows all ins and outs off. I have to kill Mach 3 and start again. I am pretty sure that every time it does this, when I restart the 4th axis DRO shows 4099.xxx? the 4th axix is angular.? I am running a gcode with a subroutine that repeats over and over with a tool change to allow inserting a new part for machining. i am also using the subroutine to make it possible to count parts.? when this failure happens is always close to the spindle motor going on or off. it is a three phase servo run by a high quality US inverter. Forgot the name right now but it is a good inverter not Chinese no name stuff. I am pretty sure the spindle motor is causing noise that kills the Pokeys. I have proper grounding and shielding.? I changed the inverter carrier frequency from the default of 5Khz to 2khz and have not had the problem yet but it some times does not happen for a considerable time.? any ideas? does the 4099 signify some overflow?? does it sound like it is inverter noise? might the lower carrier frequency be the fix? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
|
I had a lot of noise problems with my Mach 4 and a Pokeys controller using the USB interface.? My wiring was carefully done. I removed the USB cable and switched to ethernet and I have not had a problem since that time. Bertho ?
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From: [email protected] < [email protected]> On Behalf Of spencer@... Sent: Friday, March 27, 2020 12:32 To: [email protected]Subject: Re: [MachCNC] strange stopping ? i forgot to mention that, i have ferrites everywhere. that is one of the first things i do.? i have them on the signal leads to each stepper and even on the usb cable to the pokeys although the mfg suggested it would not do anything. i tried a usb signal conditioner thing but it did not work, meaning that most things plugged into it stopped working. anyone know of a signal conditioned for usb that does work? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212 ------ Original Message ------ Sent: 3/27/2020 4:03:12 AM Subject: Re: [MachCNC] strange stopping I would probably try adding ferrite beads to the leads. I have my router working really well with the following configuration. Solid state tiny computer running win 10. Mach 3 latest version Pokeys USB CNC thing connected to a PDMX. I am finally getting smooth motion no lost steps etc etc. Everything works except. Occasionally Mach3 just stops and is totally unresponsive. Can not reset, jog etc. The diag screen shows all ins and outs off. I have to kill Mach 3 and start again. I am pretty sure that every time it does this, when I restart the 4th axis DRO shows 4099.xxx? the 4th axix is angular.? I am running a gcode with a subroutine that repeats over and over with a tool change to allow inserting a new part for machining. i am also using the subroutine to make it possible to count parts.? when this failure happens is always close to the spindle motor going on or off. it is a three phase servo run by a high quality US inverter. Forgot the name right now but it is a good inverter not Chinese no name stuff. I am pretty sure the spindle motor is causing noise that kills the Pokeys. I have proper grounding and shielding.? I changed the inverter carrier frequency from the default of 5Khz to 2khz and have not had the problem yet but it some times does not happen for a considerable time.? any ideas? does the 4099 signify some overflow?? does it sound like it is inverter noise? might the lower carrier frequency be the fix? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
|
one more thing. i never had this problem until i switched to the Pokeys from the parallel port. so i am pretty sure that the noise is getting into the Pokeys through the USB cable.?
so should i put a braid over the USB cable or try to find a better shielded version and connect the ground only at the BOB ground which is common to everything else.?
my computer does not have a three wire power supply. it has "desktop" wall wart supply. i have no idea where the PC grounds are connected or if the chassis is connected to anything.
?
?
Best regards, Spencer Chase 67550 Bell Springs Rd. Garberville, CA 95542 Postal service only. Laytonville, CA 95454 UPS only. Spencer@...Spencer@...Spencer@...(425) 791-0309 (707) 223-8212
------ Original Message ------
Sent: 3/27/2020 3:58:44 PM
Subject: Re: [MachCNC] strange stopping
Electrical noise can be a bear.? Steve Spallings mentioned PC grounds and system or motor grounds.? I have his PMDX-126 and unfortunately the PC I'm using internally somewhere has the DC ground connected to the system frame which is the third earth prong on the power cord which then connects to the motor frames through the machine metal. The CUI encoders on the DC servos serve to further muck things up where their DC ground is connected to the frame.? Which is of course connected to the 3 prong and so DC ground earth ground are connected in several places. ?Shielding has no rhyme or reason here but it's one place where a single ended connection for a shield is a bit more logical. ? My EE book on electrical noise states that the signal grounds should never be connected to the DC power grounds or frame. ?The whole point of shielding is that it isolates the two. ? For your system also look at magnetic coupling.? The way a transformer works is a changing magnetic field introduces current in windings that are also in the magnetic field.? So the spindle motor current flowing through the wires can generate a field picked up encoder or limit switch wires. ?Short of what is called mu metal shielding the only solution to electromagnetic interference is distance.? Route them far apart. ? Electrostatic shielding is different.? Twisted pairs help to null out electric field noise. Shielding can be grounded at one end or both of the frame (third prong) earth.? The point is you only want the noise current flowing back through the shield into the frame.? Not through your signal wires which includes the DC 0V wires.? People tend to forget what goes out a signal wire is still a signal as it comes back through what is commonly called the ground or common wire.? (Some manufacturers have called the +5V to +24V 'common' for limit switches) ? John Dammeyer. ? ? You are trying to fix a wrong schematic with cosmetic changes. You sure have a ground loop somewhere. Check your shields, they should be connected one side only with heavy short wire to good ground. Preferably star connection. ? i forgot to mention that, i have ferrites everywhere. that is one of the first things i do.? i have them on the signal leads to each stepper and even on the usb cable to the pokeys although the mfg suggested it would not do anything. i tried a usb signal conditioner thing but it did not work, meaning that most things plugged into it stopped working. anyone know of a signal conditioned for usb that does work? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212 ------ Original Message ------ Sent: 3/27/2020 4:03:12 AM Subject: Re: [MachCNC] strange stopping I would probably try adding ferrite beads to the leads. I have my router working really well with the following configuration. Solid state tiny computer running win 10. Mach 3 latest version Pokeys USB CNC thing connected to a PDMX. I am finally getting smooth motion no lost steps etc etc. Everything works except. Occasionally Mach3 just stops and is totally unresponsive. Can not reset, jog etc. The diag screen shows all ins and outs off. I have to kill Mach 3 and start again. I am pretty sure that every time it does this, when I restart the 4th axis DRO shows 4099.xxx? the 4th axix is angular.? I am running a gcode with a subroutine that repeats over and over with a tool change to allow inserting a new part for machining. i am also using the subroutine to make it possible to count parts.? when this failure happens is always close to the spindle motor going on or off. it is a three phase servo run by a high quality US inverter. Forgot the name right now but it is a good inverter not Chinese no name stuff. I am pretty sure the spindle motor is causing noise that kills the Pokeys. I have proper grounding and shielding.? I changed the inverter carrier frequency from the default of 5Khz to 2khz and have not had the problem yet but it some times does not happen for a considerable time.? any ideas? does the 4099 signify some overflow?? does it sound like it is inverter noise? might the lower carrier frequency be the fix? Best regards, Spencer Chase
67550 Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...
Spencer@...
Spencer@...
(425) 791-0309
(707) 223-8212
|
i just checked and i do not have a shield on the USB cable. all my grounds are star config with one possible exception that might explain the problem???
i just checked and found that the shield for the power cable between the motor and the inverter is not bonded to the motor housing. it is shielded from it. the manual for the inverter suggests connecting the cable shield at the inverter ground but i didn't do that thinking that it was connected to the motor housing and therefore to the router chassis.?
the metal jacketed cable runs through various cable holding stuff but there is one place where it can touch the router chassis when it moves. might this be the reason for the totally random problem??
so, should i connect the power cable shield at the inverter and then tape over it (it is a flexible metal conduit) where it could hit the chassis? this will be easy to do.
should i put a shield over the usb cable and connect it at the pokeys end where all the grounds are common in the box that has the BOB relays etc etc?
?
?
Best regards, Spencer Chase 67550 Bell Springs Rd. Garberville, CA 95542 Postal service only. Laytonville, CA 95454 UPS only. Spencer@...Spencer@...Spencer@...(425) 791-0309 (707) 223-8212
------ Original Message ------
Sent: 3/27/2020 2:39:21 PM
Subject: Re: [MachCNC] strange stopping
You are trying to fix a wrong schematic with cosmetic changes. You sure have a ground loop somewhere. Check your shields, they should be connected one side only with heavy short wire to good ground. Preferably star connection.
? i forgot to mention that, i have ferrites everywhere. that is one of the first things i do.? i have them on the signal leads to each stepper and even on the usb cable to the pokeys although the mfg suggested it would not do anything. i tried a usb signal conditioner thing but it did not work, meaning that most things plugged into it stopped working.
anyone know of a signal conditioned for usb that does work?
?
?
Best regards, Spencer Chase 67550 Bell Springs Rd. Garberville, CA 95542 Postal service only. Laytonville, CA 95454 UPS only. Spencer@...Spencer@...Spencer@...(425) 791-0309 (707) 223-8212
------ Original Message ------
Sent: 3/27/2020 4:03:12 AM
Subject: Re: [MachCNC] strange stopping
I would probably try adding ferrite beads to the leads.
I have my router working really well with the following configuration. Solid state tiny computer running win 10. Mach 3 latest version Pokeys USB CNC thing connected to a PDMX.
I am finally getting smooth motion no lost steps etc etc. Everything works except.
Occasionally Mach3 just stops and is totally unresponsive. Can not reset, jog etc. The diag screen shows all ins and outs off. I have to kill Mach 3 and start again.
I am pretty sure that every time it does this, when I restart the 4th axis DRO shows 4099.xxx? the 4th axix is angular.?
I am running a gcode with a subroutine that repeats over and over with a tool change to allow inserting a new part for machining. i am also using the subroutine to make it possible to count parts.?
when this failure happens is always close to the spindle motor going on or off. it is a three phase servo run by a high quality US inverter. Forgot the name right now but it is a good inverter not Chinese no name stuff.
I am pretty sure the spindle motor is causing noise that kills the Pokeys. I have proper grounding and shielding.?
I changed the inverter carrier frequency from the default of 5Khz to 2khz and have not had the problem yet but it some times does not happen for a considerable time.?
any ideas? does the 4099 signify some overflow?? does it sound like it is inverter noise? might the lower carrier frequency be the fix?
?
?
Best regards, Spencer Chase 67550 Bell Springs Rd. Garberville, CA 95542 Postal service only. Laytonville, CA 95454 UPS only. Spencer@...Spencer@...Spencer@...(425) 791-0309 (707) 223-8212
|
Bertho