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Conversational Programming and NAMES- very long!
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Jon Elson
Pete Jarman wrote:
Ron wrote:Yes, in theory, a DOS program that makes no system calls, and has no TSR programs that might grab control away will be allowed to run unimpeded, and can achieve real time performance. The serial port might be a bit slow for this. But, if you are throwing Linux into the equation, who needs any extra computers? They just make debugging that much more of a hassle. If you will be using Linux, put everything on it, the real-time motion control will make sure it has adequate time to process the motion, and the rest is left to the user's various tasks. I do this now, and pretty fearlessly edit programs while the machine is running others. (The only problem is that while you are in another window, you lose keyoard and mouse focus to the machining task, so the only emergency control is the E-stop button, which is a bit drastic. Nothing like trying to switch focus with the mouse when a crash is 1/2 second away!) Jon |
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Ron Ginger
I am back from NAMES, and with a 12 hour drive had a lot of time to
think about the events there and some of my views on CNC. I have decided to become a missionary for Conversational programming, and I intend to go after FlashCut as my first convert. First, a new acronym- CPNC- Conversationaly Programmed Numeric Control. (I hereby claim ownersip of that term :-) At NAMES we had a seminar session with 10 of us each doing a short talk on our project/product, then a pannel discussion and Q&A session. We had a hard sell by an AcuRite rep pushing conversational programming. Then we had Fred smith pushing CAD/CAM, and even making a foolish statement that anyone making just one or two parts shouldnt be using CNC at all. He did get soundly shouted down on that statement! I am convinced that there is a need for CPNC. I think the entire audience at NAMES fits exactly the profile of a CPNC user. A single machinist, working in a very low budget shop with refurbed or home made tools, making one-off 'things'. These guys do not need, and are quite likely to never buy complex CAD/CAM tools. They do not have an eningeering department to generate their programs for them. They often make parts with NO drawings- either to make repair parts for some device or to model some real thing they own- from simple tools to entire tractors. They do not make 3D molds or turbine blades. Most of them are computer novices. Ok, so some segment of the world NEEDS CPNC. Another segment of the world really needs G-code CNC and CAM software, and there are already a bunch of companies supporting them. What I intend to work on is the CPNC world. I have made a start at a CPNC program. Feedback form most guys that looked at it was positive, and since I based it alot on AcuRite I thik I have a good model to work from. It still needs a lot of work but its a start. I want to get a forum started that will discuss and develop a better model for CPNC. I will put my code into a GPL form to start this discussion. QUESTION Should we carry on this discussion here on this list or start a new list devoted to CPNC? Remember, this is going to need to get into a lot of detail if we are going to really develop a good package, and we are going to have to exchange large files and screen shots. Now, why did I say that FlashCut would be my first convert? I like Visual Basic as a development tool, and I think it has more than ample capability for the GUI parts of CPNC. Although there is work in progress, no one has a VB like tool for Linux yet. I hate Windows -(3.1, 95 98 or 2000) for its lousy real time ability. This will not change in the foreseeable future. I like Linux ( In real life I am Directotr of Operations for a company and I have standardized ALL my systems and employees on Linux) I can handle Linux, but I think a lot of people that need CPNC cannot. Maybe someday they will be able to, but not yet. The only way to make a decent CPNC system with a windows GUI is to use a separate motion controller box to handle the real time stuff. We had some discussions here a few weeks ago about developing such a box, but that died. FlashCut has a nice one, and its cheap enough to be widely used. BUT- they refuse to release the specs to program it. I harped on this at NAMES to anyone that would listen. I told alot of guys to avoid buying FlashCut because they were offering a closed package that could not be expanded. If you buy FlashCut now you better like the program, because its the ony one you can run- did anyone ever buy a stereo that only came with one song? So, if we can get FlashCut to open their protocol we can develop a CPNC package to use it. I dont expect them to NOT sell their software, I just want the ability to buy their package and run MY software on it. I cannot see how this could do anything but enlarge their market. So, does anyone from FlashCut read this list? does anyone know anyone at FlashCut that would read this message? if so, please forward it to them. Now we could reverse engineer the protocol- its a serial port and would be easy to tap into, but I dont want to do that- why should I write software to help sell their hardware if they are not going to cooperate? My first choice then is to develop CPNC on windows to support the FlashCut controller, but if we are careful in its design the gui aspects of it should work just as qwell driving an EMC/Linux system. Only the interface part would need to be altered. I think I have now set the record for the longest post to this list, so its time to hang up. Anyone going to join me in building a great CPNC system? ron e-mail to ginger@... or ginger@... web: |
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Mike Mueller
I give up, what exactly is the difference between Conversationaly Programmed
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Numeric Control and regular CNC ? Sorry, I just had to ask. Mike Mueller First, a new acronym- CPNC- Conversationaly Programmed Numeric Control. |
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james owens
Ron,
I, for one, am right behind what you say here but I fear that this is another project that will die on the list. It can only lead to more choice, and possibly confusion, in the CNC forum. I hope that you keep this discussion on this list regardless of how technical it becomes. Most of the post will not be understood by a lot of its members but there is always the hope that some will rub off. The distaste you have for the Windows Operating System, I sure, is shared by all that use computers for more than writing letters. The reality is that most of the computers that sit in homes around the world use this system. We need a program that is easy to use and will not take weeks of study, with little backup, to get to grips with it. After all it is about cutting material. To this end why is not possible for you to release the programming you have already written while the next generation is in gestation. My workshop is still in the conversion stage with the hardware incomplete. Being an ACAD user the CAD/CAM option is the one that will be used even for one-offs. Even the cut-off saw will be controlled, probably via a stepper and PIC micro. However the facility to machine a figment of my imagination without a drawing does appeal, this was the way that things used to be manufactured in my workshop. I have forwarded the body of your posting to FLASHCUT without including your email address. Terry. |
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snapscottc@yahoo.com
I do belive that a good name for it CPNC. (do I owe you a fee for
using this name?) My son uses both a mill and lathe that can be programed in that fashon I would love to have a machine that I could program from the machine to do repeted things. Or bolt circles or tapers or what ever. Scott C. |
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Paul Devey
Ron,
You have given us lots to think about. Here are some random babblings to chew on: 1. CAD/CAM tools: agreed, most of us hobbyists do not have the time or requirements for these tools. CPNC will suffice for 90% of what we do. 2. Use of FlashCut HW: An lpt interface would still be nice. Can you describe your Win performance problems? 3. GPL release: Ron, thank you for your generosity. 4. QUESTION: Should we carry on this discussion here on this list or start a new list devoted to CPNC: I suggest we make it a separate forum for development. Support and could be handled here at CAD_CAM_EDM_DRO. 5, The only way to make a decent CPNC system with a windows GUI is to use a separate motion controller box: Too bad. Their are a lot of CNC-parallel port controllers out there. Using FlashCut HW may slow down the adoption of this fine product. Maybe when Hans returns he might take on designing a new controller with a PIC to perform IRQ functions. Paul Devey |
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Pete Jarman
Ron wrote:
<The only way to make a decent CPNC system with a windows GUI is to use a <separate motion controller box to handle the real time stuff. We had <some discussions here a few weeks ago about developing such a box, but <that died. Is there any way that the motion controller box could be an outdated x86 PC with an interface card running a real time programme under either DOS or linux? The software would handle incoming commands and report status through the serial port to the controlling PC running the GUI and the conversational programming software. Pete Jarman North of Bedford, England |
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Jon wrote:
[snipsnipsnip] (The only problem is that while you are insounds like a "slide hold" button is needed there! I haven't looked into the code yet but wouldn't dropping the feed override to zero in response to an external signal do this? Brian |
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James Eckman
The only way I know of to get around the tendency of Windows 95+ and NT
to go to sleep is to use some form of intelligence in the controller. "Real time" NT apparently isn't. There are PC cards made by Oregon Microsystems and the like that have large command buffers and can perform lots of coordinated movements without PC intervention. They are not cheap however. Other options include DOS and RTL linux, DOS can be made to work for sure! Others in the group have had great success with Linux. The 5 minute install for EMC would make it vastly more popular with hobbiests! I'd even give it a shot... Jim |
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Ray Henry
Brian wrote
Jon wrote: [snipsnipsnip] (The only problem is that while you are insounds like a "slide hold" button is needed there! I haven't looked into the code yet but wouldn't dropping the feed override to zero in response to an external signal do this? Yes feedhold commands are available and effective during any motion caused by EMC. (manual, auto, mdi, home) The effect of feedhold is the same as pause when emc is in auto mode. The problem becomes figuring out how to make a feedhold/pause available to the operator who is "fearlessly editing" something else. For those who use the Tcl/Tk gui's, it would be possible to place a feedhold button on the bottom of all of the genedit editors and bind this to some keystroke. Ray |
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Darrell
Jon, What you say may be true for servo but not for steppers. To make
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steppers work properly we need something past the Linux box to create smooth step pulses. The problem with EMC and steppers now is that the pulse train is ragged and you reach a point at about 20 IPM where the jitter on the pulse train exceeds the instantaneous move capability of the stepper motor and it stalls. Darrell ----- Original Message -----
From: Jon Elson <jmelson@...> To: <CAD_CAM_EDM_DRO@...> Sent: Sunday, May 03, 1998 8:52 PM Subject: Re: [CAD_CAM_EDM_DRO] Conversational Programming and NAMES- very long! discussion of shop built systems, for CAD, CAM, EDM, and DRO.
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Jon Elson
Ray Henry wrote:
Jon wrote:Well, I'm working on a flexible interface to replace the STG card, but it could do a lot of other things, too. So, I'm planning on making a real pendant, with jog dials, override controls, etc. that would be connected to the GUI directly, rather than through the X interface. What had been holding me back was deciding how to connect the pendant to the PC. Jon |
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Darrell,
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On my EMC install I can get up to 80 ipm or so and that is WAY beyond the instantaneous move capability of my steppers. I am running the freqmod setup on an AMD K6 500. If you are running the older steppermod or are running freqmod on a slow machine you will poop out at a slower rate, but 20 ipm seems like you have something else going on or require a very high number of steps per inch. Tim [Denver, CO] ----- Original Message -----
From: Darrell <dgehlsen@...> To: <CAD_CAM_EDM_DRO@...> Sent: Thursday, May 04, 2000 11:57 AM Subject: Re: [CAD_CAM_EDM_DRO] Conversational Programming and NAMES- very long! Jon, What you say may be true for servo but not for steppers. To make steppers work properly we need something past the Linux box to create smooth step pulses. The problem with EMC and steppers now is that the pulse train is ragged and you reach a point at about 20 IPM where the jitter on the pulse train exceeds the instantaneous move capability of the stepper motor and it stalls. Darrell |
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Darrell
Tim,
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I am running an AMD K6 II 400 and only require 2000 steps per inch. I am running freqmod Feb 29 I believe. When I tried it on my Bridgeport, movement started getting ratty at 15 IPM and maxed out at 20 IPM. Looking at the pulse train with a scope, pulse jitter (timing between steps) got worse up to 20 IPM and then smoothed out to near perfect at 30 IPM and then started going bad again. At 20 IPM the pulse train was varying by as much as 3/4s of the signal width. I talked to Fred Proctor and he agreed that timing in EMC was the problem. Using micro stepping and small motors would probably let you move much faster but with 1100 oz in motors and full stepping on the Bridgeport it requires a clean signal. I am used to getting 120 IPM. I have used the Microkinetics 8010 drivers with good success and I think the problems that users have been having on this group is directly related to the poor step signal timing. Darrell ----- Original Message -----
From: Tim Goldstein <timg@...> To: <CAD_CAM_EDM_DRO@...> Sent: Thursday, May 04, 2000 12:05 PM Subject: Re: [CAD_CAM_EDM_DRO] Conversational Programming and NAMES- very long! Darrell,setup on an AMD K6 500.smooth step pulses. The problem with EMC and steppers now is that the pulse traindiscussion of shop built systems, for CAD, CAM, EDM, and DRO.
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Interesting...
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When I talked to Matt Shaver about his Bridgeport conversion he said he was able to get 60 ipm if I remember correctly. Makes you wonder why he managed 3X the speed you are getting?? Tim [Denver, CO] ----- Original Message -----
From: Darrell <dgehlsen@...> To: <CAD_CAM_EDM_DRO@...> Sent: Thursday, May 04, 2000 4:09 PM Subject: Re: [CAD_CAM_EDM_DRO] Conversational Programming and NAMES- very long! Tim,movement started getting ratty at 15 IPM and maxed out at 20 IPM. Looking at theof the signal width. I talked to Fred Proctor and he agreed that timing inEMC was the problem.the problems that users have been having on this group is directly related to |
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Matt Shaver
From: Tim Goldstein <timg@...>54ipm to be exact, perhaps it's because I was using a scale of 4000, I don't know for sure. That said, Darrell is right, the stepper pulse output of the EMC, even using freqmod, isn't good enough for some machine configurations. I think it's a combination of things: 1. The machines Darrell and I are trying to retrofit have much more mass in each axis to sling around than a mill drill or Sherline, or even a Shoptask, although they're closer to Bridgeport size than most hobbiest machines. 2. The motors Darrell and I are using are old technology. Most hobbiests use newer motors with greatly superior characteristics. 3. People who buy a Bridgeport retrofit expect rapid feed rates of at least 100 ipm (the stock machine would do 120 ipm), while most Sherline operators could probably get by with 50 ipm ;) . AFAIK the existing control programs that are capable of high output steps rates _AND_ close grained frequency control of the step rate _AND_ negligible jitter use external hardware (outside the standard PC) to generate or somehow control the step pulses. Examples of these are AHHA, and Flashcut. For reasons that take about a page of typing to explain (see the archives), software only solutions break down at high step pulse rates. The one possible exception to this is Indexer LPT, although I don't have personal experience with it (does anyone here use it?). I would love to know if anyone has done any experiments to measure the performance of I-LPT, specifically I'd like to know the granularity of the frequency control from DC to it's maximum output rate and the guaranteed maximum jitter (however they would like to specify it). If it turns out that I-LPT achieves all the three above mentioned performance goals _AND_ still allows the user interface to operate normally while the machine is in motion, then it's definitely worth the price charged. The approach I would use (will use if I ever do anything else with steppers) would be to employ an external programmable frequency generator, probably in the form of an Intel 8254 CTC that would be controlled by the EMC software. The step signals (from the 8254's output) and the direction signals (from a general purpose digital I/O port) would go to the stepper motor drive circuitry and also be fed back into a counter circuit (like the LSI Logic 7266) that would accumulate the position count for each axis. To the EMC this would look just like a servo system. The EMC would send out velocity commands to the 8254 and read back position data from the counter. This servo loop would be processed at a kilohertz or so just like any other servo system. In fact, you could get position feedback from a linear scale if you would prefer and that wouldn't change anything in the software (actually there are a few issues such as the difference in resolution between one stepper step and one encoder count, but this could be worked out). It's interesting to note that this is exactly a mirror image of the approach taken by Bill Wainwright with his Servo-Lite setup. Matt |
As Far As I Know, that's what it means. Paul -- Paul Amaranth | Rochester MI, USA Aurora Group, Inc. | Systems & Software paul@... | Unix / Windows / NT |
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