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Olivier:

Actually, this question revolved around my Bridgeport mill. In this
case I'd like to get "feedback" to MACH2 and to a readout of RPM, but
I don't think the number is as critical as in a lathe. I just
thought it made sense to use the pulses from the VFD to drive the
readout. An error of a percent or two probably wouldn't matter for
this application. It's just that the number of pulses would have to
be able to be scaled to make the read out make sense in RPM. Is
there a way to scale in MACH2 between the pulses and the RPM?

Jeff

--- In mach1mach2cnc@..., "Digital audio Pro"
<digitalaudiopro@w...> wrote:

Not enough precision for threading. Even if you could do a PWM to

pulse

convertor it will not work. You will need a true encoder, home made

or not.

More, it will be simpler.

For threading you don't only need the exact speed of the spindle,

but his

absolute position too with a good accuracy. Can only be done with

an encoder

with index + eventually other pulses for low or medium speed

applications.

Olivier.

Not enough precision for threading. Even if you could do a PWM to pulse
convertor it will not work. You will need a true encoder, home made or not.
More, it will be simpler.

For threading you don't only need the exact speed of the spindle, but his
absolute position too with a good accuracy. Can only be done with an encoder
with index + eventually other pulses for low or medium speed applications.

Olivier.

You are wrong, it is the opposite.

It has been collectively decided for the first mach2 threading
implementation that carriage moves need to be slave of the spindle. This is
for compatibility with hobbist retrofited lathes, because a servo system is
too expensive for them.

So you don't need a spindle speed control, just an encoder on the spindle to
instruct mach2 how to coordinate the carriage moves. There is some options
here, only one index, or index + separate pulses (max 255 PPR) , or combined
index + pulses with a home made disk (the index need to be 50 % larger than
other slots). 8 - 32 PPR seem to be a good value for most low or medium
speed applications. For high speed (> 500 - 1000 RPM ) only 1 index seem to
be enough thanks to spindle inertia.


But it will be certainly better if you use a VFD with open loop or closed
loop speed correction to stabilize spindle rotation. This will make things
easier for the mach2 synchronizing engine.


For special low speed applications, where you need combined and synchronized
spindle - carriage moves (for non circular parts for example, or spindle
indexing + brake), it's possible to use an angular axis (A, B or C) to
control a servo spindle with step - direction signals. But a true servo
spindle for threading is not actually implemented.

When it will be implemented, i don't think a normal VFD will be enough. You
will need at least a closed loop VFD with vector control option (not really
cheap....).

Nevertheless the actual implementation seem to work very nicely according to
the last reports.

Olivier.

--- In mach1mach2cnc@..., <james_cullins@s...> wrote:

I tried to order one of these probes and they don't have them in stock.
Jim

I noticed that. Does that mean they can't be got? Or does it mean there will be a
long lead time? Or maybe you have to buy 10,000 of them? I've found that to be the
case many times. Sometimes you can only buy in large quantities as a distributor.

Ross

Hi Jeff:

The spindle control for speed is not a necissity for threading, a
manual speed control will work fine. The only prerequisite for
threading is a sensor to detect the actual spindle speed and zero
point.

Its nice to have speed control but not necessary...

Thanks,
Art

John:

To use the index input you must be using a *.lset screen layout.
It is not good enough to rename Y to Z, you must use Z properly.
You'll know if the index is working by looking at the actual RPM
DRO , if is displaying an RPM, then your index is working fine.

Art

I notice that "index pulse" can be checked on the parallel input to
pick up the true speed of a machine. Can the PWM frequency of a VFD
be used for this? If so, can it be scaled in MACH2 to correspnd to
the speed (I believe speed is a linear function to frequency, but the
numeric value of one will not be the same as the other.

Jeff

Note: This machine is one of those 3 in 1 combinations so to switch
to lathe should I be setting up a new lathe screen using XY? Sorry
that previous post didn't include this 3 in 1 info.

--- In mach1mach2cnc@..., "Bloy2004" <jmnotions@c...>
wrote:

gee I'm feeling dense....
I've set up the sensor but haven't been able to witness its
function in the readouts. I believe it's okay but do I have to re-
wire the motors/signals to conform to the XZ for lathe? Or, can I
just use XY and re-lable the Z DRO to Y to get the axes I want?

In

mill the Z is the spindle axis..but in lathe the Z won't be used?

oh boy... I'm confused....
Help...
John

I am considering changing my manual Logan lathe to CNC. I am unclear
as to how the carrage speed is coordinated with the spindle feed to
allow threading. Is a VFD to an induction motor on the spindle good
enough for speed control or does it have to be a servo (or have I got
the concept completely wrong)?

Thanks
Jeff

Hello Art,

Can you please post the sequence needed to initialize the OCX
Maybe some demo code you used to test the OCX.
I can use the OCX in VB without crashes, however I did not get any
motion yet and after a while I get "out of memory"

Any help will be gratly apreciated

Best regards
Peter



--- In mach1mach2cnc@..., Art <fenerty@a...> wrote:

Hi All:

The OCX is now functioning properly from VB as well.

On Monday 01 March 2004 00:33, Steve Blackmore wrote:

On Mon, 01 Mar 2004 00:07:15 -0000, you wrote:

Can anybody suggest a low priced Cam software that is fairly user
friendly.

Dolphin Partmaster

Very reasonably priced and an easy learning curve.

See



There are post processors for both Mach2 Mill and Lathe available.

Not only that, but it has its CAD package effectively free too!! ... if you
want a CAD package that can do DXF export at a VERY good price ( err ..
nothing!! ) then it is recommended.

The download says its a 'trial' version, I'm not sure what the difference is
between that and a full version, but it seems to be all there ... saves,
exports etc etc etc .. teamed up with Mach2 that becomes a very interesting
little package ....


--
RapidCut CNC Technology

CNC Plasma Cutter

By the way, Art wrote the hookup scheme... I just reitterated...

--- In mach1mach2cnc@..., "Bloy2004" <jmnotions@c...>
wrote:

Okay! After not being able to sleep, I got the spindle index

pulse

to register! Apparently there was insufficient contrast between

the

background(pulley) and the white reflective tape. Taking a

reading

of difference of voltage from the contrasts yielded very little
change. Painting the pulley reading area black solved the
problem....now get 4.87V black and 10.1mv white! .... which, I
think, indicates active low.

--- In mach1mach2cnc@..., "Bloy2004" <jmnotions@c...>
wrote:

this is how it is wired..
There are 4 pins on the sensor. Hook the out pin to the printer

port

pin,
hook the 5volt to a 5v source, the common pin to the printer

port

pin 25 as
well as the 0vdc line of the 5volt supply your using, and for

the

LED, you
hook a resistor between L and 0vdc. The value determines how
sensitive it
is. I used a 200Ohm and it seems to work fine..

I have the index-pulse ticked and the timing-pulse ticked in
the "input signals". and assigned both to pin 15.
What else do I need to do?

Okay! After not being able to sleep, I got the spindle index pulse
to register! Apparently there was insufficient contrast between the
background(pulley) and the white reflective tape. Taking a reading
of difference of voltage from the contrasts yielded very little
change. Painting the pulley reading area black solved the
problem....now get 4.87V black and 10.1mv white! .... which, I
think, indicates active low.

--- In mach1mach2cnc@..., "Bloy2004" <jmnotions@c...>
wrote:

this is how it is wired..
There are 4 pins on the sensor. Hook the out pin to the printer

port

pin,
hook the 5volt to a 5v source, the common pin to the printer port
pin 25 as
well as the 0vdc line of the 5volt supply your using, and for the
LED, you
hook a resistor between L and 0vdc. The value determines how
sensitive it
is. I used a 200Ohm and it seems to work fine..

I have the index-pulse ticked and the timing-pulse ticked in
the "input signals". and assigned both to pin 15.
What else do I need to do?

Daniel

Take a look at Dolphin CAD/CAM, a download is
available from www.dolphin.gb.com <> . This
product has
CAD, Mill, Turn, Wire EDM, Involute Gear Design and
Serial Comms modules.

Contact me offlist with your location and I
Can point you in the direction of an agent who can
Supply at a hobbyist price.

Regards

Michael Milligan
Dolphin Cad Cam Systems Ltd

--- In mach1mach2cnc@..., "mmenig" <mmenig@y...> wrote:

Hi
Can anybody suggest a low priced Cam software that is fairly user

friendly.

thanks

Daniel

maybe the cheaper visual mill?



What did you need it for anyway? mill lathe? router? engraving?

I tried to order one of these probes and they don't have them in stock.
Jim

On Sunday 02 March 2003 14:27, Robert Campbell wrote:

Peter,

I have used Adobe Streamline in the past. It worked very well. I have also
done a manual trace with Rhino. Corel Has a program called Corel Trace.

google for 'raster vector' and there is a freeware program called 'win topo'
.. seems to work for me.

Bob Campbell
Bob@...
www.campbelldesigns.com
Breakout board
THC board sets
CNC router plans
Stepper Motors
----- Original Message -----
From: "Peter Cruickshank" <crankshaft_sg@...>
To: <mach1mach2cnc@...>
Sent: Sunday, February 29, 2004 12:50 AM
Subject: [mach1mach2cnc] Raster to Vector Converion

Hi;

Rather than me re-inventing the wheel, has anyone evaluated the
varoious utilities for converting raster images to vector ??

I am interested in this primarily to use MACH for engraving and
since it's a hobby the best balance of functionality & price are of
course important.

I'm not sure what features I should look for, I guess the ability to
clean up images, smooth curves etc would be useful, i guess they all
export in .dxf format which is compatible with MACH ??!

Any recommendations greatfully accepted !

Thanx

PeterC







Yahoo! Groups Links

Yahoo! Groups Links

--
RapidCut CNC Technology

CNC Plasma Cutter

With Mach2 just either check or un-check it should take it either way.
Jim

--- In mach1mach2cnc@..., "rrc62_03782" <rrc62@a...>
wrote:

Someone

posted an interesting probe switch on another board but it is a

normally closed

switch.

Thanks...Ross

Could you post where that probe was mentioned? I'd like to read
about it.
Thanks,
JohnM