[Emc-users] EMC as PLC
Is it possible to somehow set the EMC to work as PLC, totally autonomous with some options of g-code control? Regards Klemen - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] stepper config
Can you tell me what parts you see on the screen that don't match the book and in which manual? I'm in the process of organizing the manuals most of which will come out with 2.2.6. For a really short description of getting up and running once you have the liveCD installed. 1 run the latency test 2 gather your info about your hardware 3 run stepconf and test each axis 4 make a shortcut on your desktop to your config 5 test your machine John On 13 Jul 2008 at 19:30, Cindee Lichter wrote: I agree. I've tried so many different times that I have a big list that doesn't make any sence so now I'm loading ubuntu for the 4th time. I sure wish what I see in the book and what I see on he screen looked the same. John --- On Sat, 7/12/08, Ray Henry [EMAIL PROTECTED] wrote: From: Ray Henry [EMAIL PROTECTED] Subject: Re: [Emc-users] stepper config To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Date: Saturday, July 12, 2008, 7:19 AM IMO this sounds like a case of creating one configuration but running another. Make certain that the config picker is pointed to the config that you just made. I tend to do this by choosing a really strange or specific config name like mylittlestepperscara or some such. HTH Rayh On Sat, 2008-07-12 at 07:05 -0600, John Thornton wrote: A bit more information is needed to help you. Try and be as specific as possible when describing a problem. List each step you took to arrive at your problem. SWAG, sounds like your test program and the Stepconf config are not the same... John On 11 Jul 2008 at 10:08, Cindee Lichter wrote: I am very new to this so please bare with me. I did a lot of checking with LEDs on the parallel port before I actually moved on to a stepping motor driver. But when I did it all worked and the motor moved as the program I had installed to test it tld it to. I could tell needed to config it btter so I went through that program. I used the test this axis button and got it where it was working really well. so I applyed it. When I went back to my test program nothing happens. I went back to the config program and again it works fine. (and my changes were there). What am I missing? John -- --- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- --- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08
[Emc-users] livecd Ubuntu 8.04 Hardy Heron fails on boot
Hello, Wanting to try out EMC2, I just downloaded the livecd based on *Ubuntu 8.04 Hardy Heron. * however booting from the cd fails immediately on start with following message: ISOLINUX 3.53 Debian-2007-12-11 Unknown keyword in syslinux.cfg. Unknown keyword in syslinux.cfg. Unknown keyword in syslinux.cfg. Missing parameter in syslinux.cfg. Unknown keyword in syslinux.cfg. Could not find kernel image: linux boot: Within windows, the cd (autorun) comes up with Ubuntu CD Menu. the contents of the cd seem fine. I tried to boot the cd on two different laptops, but got the same error. I cannot try booting from my desktops (all busy at the moment). Searching the archives did not yield a result. What am I doing wrong? (now downloading the ubuntu 6.06version to give that a go) best regards glenn - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] livecd Ubuntu 8.04 Hardy Heron fails on boot
the only idea I have is that there might have been a problem during burning... did you verify the md5sum of the cd before writing? Regards, Alex - Original Message - From: glenn de moor [EMAIL PROTECTED] To: emc-users@lists.sourceforge.net Sent: Monday, July 14, 2008 1:46 PM Subject: [Emc-users] livecd Ubuntu 8.04 Hardy Heron fails on boot Hello, Wanting to try out EMC2, I just downloaded the livecd based on *Ubuntu 8.04 Hardy Heron. * however booting from the cd fails immediately on start with following message: ISOLINUX 3.53 Debian-2007-12-11 Unknown keyword in syslinux.cfg. Unknown keyword in syslinux.cfg. Unknown keyword in syslinux.cfg. Missing parameter in syslinux.cfg. Unknown keyword in syslinux.cfg. Could not find kernel image: linux boot: Within windows, the cd (autorun) comes up with Ubuntu CD Menu. the contents of the cd seem fine. I tried to boot the cd on two different laptops, but got the same error. I cannot try booting from my desktops (all busy at the moment). Searching the archives did not yield a result. What am I doing wrong? (now downloading the ubuntu 6.06version to give that a go) best regards glenn - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] resolver to quadrature converter
Jon, I'm the guy from the CNC Workshop that had the Yaskawa encoder documentation you needed for testing the resolver to quadrature conversion. I also had the Panasonic servo motors / drives and a lot of other junk for sale there. Have you looked at the AD650 (also from Analog Devices)? I've never used any, but the data sheet looks like it might have potential. Here's a (really long) link to the data sheet. The AD650 is easy to find on their web site too if this long link fails. http://www.analog.com/static/imported-files/data_sheets/AD650.pdf#xml=http://search.analog.com/search/pdfPainter.aspx?url=http://www.analog.com/static/imported-files/data_sheets/AD650.pdffterm=f/vfterm=f/vla=en Regards, Steve Jon Elson wrote: I mentioned to some people at the CNC Workshop that I was working on a resolver to quadrature converter board, and we hooked one up to a servo motor to compare a real encoder against the AB signals derived from the resolver. That all worked quite well. Well, a customer also wanted a velocity signal from it to simulate a DC tachometer. I said Oh, simple, it has a digital velocity output, I'll just hook that to a DAC and it is done! Ahh, not so fast. The AD2S1200 chip is designed to run up to 1000 RPS = 60,000 RPM, so if full scale of 2047 (12-bit signed binary value) is 60,000 RPM, then one bit = 29 RPM. Oh oh, that is never going to work to close the loop of a positioning servo like on a machine tool axis! I've confirmed by twirling the resolver shaft that this appears to be the true scale factor for the chip. So, I am going to have to develop the velocity value from the quadrature signals. Since the chip interpolates the resolver to 4096 counts/rev, I should be able to produce much better resolution at reasonable speeds. For instance, at 60 RPM, you get 4096 counts/second. At 100 counts/second, it would be turning only ~1.5 RPM, so some really simple filtering should work. I'm trying to decide if I should do this digitally or have encoder counts produce fixed-width pulses on a pair of charge pumps, one on each input to a differential amp. Digital would get rid of all the adjustment pots, of course. Any thoughts? Jon - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] resolver to quadrature converter
Jon, I just noticed the data sheet for the AD650 contains a link to an application note specific to F/V conversion. The link is broken, but I did find it after some searching. It seems like the hard part will be at or near zero speed. Here's a link to it anyway... http://www.analog.com/static/imported-files/application_notes/75729603AN-279.pdf#xml=http://search.analog.com/search/pdfPainter.aspx?url=http://www.analog.com/static/imported-files/application_notes/75729603AN-279.pdffterm=applicationfterm=notesfterm=279fterm=application%20notes%20279la=en Regards, Steve Steve White wrote: Jon, I'm the guy from the CNC Workshop that had the Yaskawa encoder documentation you needed for testing the resolver to quadrature conversion. I also had the Panasonic servo motors / drives and a lot of other junk for sale there. Have you looked at the AD650 (also from Analog Devices)? I've never used any, but the data sheet looks like it might have potential. Here's a (really long) link to the data sheet. The AD650 is easy to find on their web site too if this long link fails. http://www.analog.com/static/imported-files/data_sheets/AD650.pdf#xml=http://search.analog.com/search/pdfPainter.aspx?url=http://www.analog.com/static/imported-files/data_sheets/AD650.pdffterm=f/vfterm=f/vla=en Regards, Steve Jon Elson wrote: I mentioned to some people at the CNC Workshop that I was working on a resolver to quadrature converter board, and we hooked one up to a servo motor to compare a real encoder against the AB signals derived from the resolver. That all worked quite well. Well, a customer also wanted a velocity signal from it to simulate a DC tachometer. I said Oh, simple, it has a digital velocity output, I'll just hook that to a DAC and it is done! Ahh, not so fast. The AD2S1200 chip is designed to run up to 1000 RPS = 60,000 RPM, so if full scale of 2047 (12-bit signed binary value) is 60,000 RPM, then one bit = 29 RPM. Oh oh, that is never going to work to close the loop of a positioning servo like on a machine tool axis! I've confirmed by twirling the resolver shaft that this appears to be the true scale factor for the chip. So, I am going to have to develop the velocity value from the quadrature signals. Since the chip interpolates the resolver to 4096 counts/rev, I should be able to produce much better resolution at reasonable speeds. For instance, at 60 RPM, you get 4096 counts/second. At 100 counts/second, it would be turning only ~1.5 RPM, so some really simple filtering should work. I'm trying to decide if I should do this digitally or have encoder counts produce fixed-width pulses on a pair of charge pumps, one on each input to a differential amp. Digital would get rid of all the adjustment pots, of course. Any thoughts? Jon - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Using own driver and other newbie questions
One possible approach is to start with the sim configuration, in which position commands are looped back to position feedback. Yes, I think this would probably be the best thing to do; I really have no need for the realtime behaviour as such. Add to this a sampler RT component which also copies the position commands and whatever other data you want to a fifo that is read by userspace, then have your userspace program read the output of halsampler and sends it to your device. You lost me here, due to my very limited knowledge of the emc source structure... :-) Would it be possible for you to point me to a few source files? I think I would also need to sync the time sensed by emc with the time used on my machine; otherwise they would get out of sync quite fast. My current idea is to write a small layer (if at all possible) using named pipes between a user-space program and emc; this way anyone can add their own (non-realtime) machines to emc... It should be possible to do this completely without using a realtime kernel (not that this is a problem as such) but obviously I have to dig a little deeper into the source... Currently I have just been able to compile the entire system in simulation mode, which is really all I need. Best regards Preben - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Tandem Axes-YY
Hello, I just nearly completed the project of retrofitting of CNC router, with tandem configuration on the Y-axes (i.e. 2 motors on the Y movemet). Can I get help from members who had done the setting of homing sequence in HAL for this tandem YY? The controller used is univpwm system from Pico. I am relatively new to EMC2, and just would like to see the machine start cutting ornamental wood design with subD and nurb surfaces. My bobby is woodworking. Thank you, Lie - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] resolver to quadrature converter
Hi Steve, Jon: The Analog Devices chips have really good specs especially at low freq. How they are rather pricey in todays world of inexpensive chips with excellent performance. A couple of $14 to $31 chips drives the price of the finished board up pretty fast. There is a National tach chip ( LM2917) at much lower prices but also lower specs. I wonder how well a digital approach with a simple moving average would work. I'm assuming that a good digital filter would take too much time to compute but that is someone else's problem. ;-) Dave On Jul 14, 2008, at 4:45 AM, Steve White wrote: Jon, I just noticed the data sheet for the AD650 contains a link to an application note specific to F/V conversion. The link is broken, but I did find it after some searching. It seems like the hard part will be at or near zero speed. Here's a link to it anyway... http://www.analog.com/static/imported-files/application_notes/ 75729603AN-279.pdf#xml=http://search.analog.com/search/ pdfPainter.aspx?url=http://www.analog.com/static/imported-files/ application_notes/ 75729603AN-279.pdffterm=applicationfterm=notesfterm=279fterm=appli cation%20notes%20279la=en Regards, Steve Steve White wrote: Jon, I'm the guy from the CNC Workshop that had the Yaskawa encoder documentation you needed for testing the resolver to quadrature conversion. I also had the Panasonic servo motors / drives and a lot of other junk for sale there. Have you looked at the AD650 (also from Analog Devices)? I've never used any, but the data sheet looks like it might have potential. Here's a (really long) link to the data sheet. The AD650 is easy to find on their web site too if this long link fails. http://www.analog.com/static/imported-files/data_sheets/ AD650.pdf#xml=http://search.analog.com/search/pdfPainter.aspx? url=http://www.analog.com/static/imported-files/data_sheets/ AD650.pdffterm=f/vfterm=f/vla=en Regards, Steve Jon Elson wrote: I mentioned to some people at the CNC Workshop that I was working on a resolver to quadrature converter board, and we hooked one up to a servo motor to compare a real encoder against the AB signals derived from the resolver. That all worked quite well. Well, a customer also wanted a velocity signal from it to simulate a DC tachometer. I said Oh, simple, it has a digital velocity output, I'll just hook that to a DAC and it is done! Ahh, not so fast. The AD2S1200 chip is designed to run up to 1000 RPS = 60,000 RPM, so if full scale of 2047 (12-bit signed binary value) is 60,000 RPM, then one bit = 29 RPM. Oh oh, that is never going to work to close the loop of a positioning servo like on a machine tool axis! I've confirmed by twirling the resolver shaft that this appears to be the true scale factor for the chip. So, I am going to have to develop the velocity value from the quadrature signals. Since the chip interpolates the resolver to 4096 counts/rev, I should be able to produce much better resolution at reasonable speeds. For instance, at 60 RPM, you get 4096 counts/second. At 100 counts/second, it would be turning only ~1.5 RPM, so some really simple filtering should work. I'm trying to decide if I should do this digitally or have encoder counts produce fixed-width pulses on a pair of charge pumps, one on each input to a differential amp. Digital would get rid of all the adjustment pots, of course. Any thoughts? Jon - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- --- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/ cca08___ Emc-users mailing list Emc-users@lists.sourceforge.net
Re: [Emc-users] stepper config
On Sun, 2008-07-13 at 19:30 -0700, Cindee Lichter wrote: I agree. I've tried so many different times that I have a big list that doesn't make any sence so now I'm loading ubuntu for the 4th time. Hi John One small thought for those sorta new to Linux is that you need not reload the computer to fix the small sorts of issues created during an EMC setup. Linux is way robust for that task. In fact you could simply go into your home directory and delete the emc2 sub directory and the next time you start up emc and select a config it will ask if you want to save it. I believe the same is true of stepconf if you start a new config there without an emc2 directory present. After you have your next run at a config, I suggest you get that box on the web and use an IRC client to connect to irc.freenode.net and join the emc channel. That way we can work on the issue with you right on the box you are setting up. Rayh - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Emc-users Digest, Vol 27, Issue 20
Hello Alex, Thank you for the reply. -the md5 for the 8.04 emc2 version is different than mentioned on the website (1f30fb07a22ae3e2cf17c486f41e1c9a) Strange as I downloaded the same file again to be sure. both copies return as md5 1f30 -I then dl'ed the 6.06 version (which yields the correct md5) While that boot ran further, it halted with a fault related to the gnome gui. -to be sure my laptop was not the cause ( fujitsu lifebook s7010), I ran the latest ubuntu livecd 8.0.4.1 that worked fine. (ouf) -I now got the emc2 v804 from the eu-mirror and that gave the correct md5 (91c5abb84386091e0ff056e9ebc40fdb) I'm burning it right now..., testing result the boot runs all the way through - nice background :) it seems I got a working cd now. thanks for your help glenn [EMAIL PROTECTED] wrote: 8 Message: 1 Date: Mon, 14 Jul 2008 13:55:34 +0300 From: Alex Joni [EMAIL PROTECTED] Subject: Re: [Emc-users] livecd Ubuntu 8.04 Hardy Heron fails on boot To: Enhanced Machine Controller \(EMC\) emc-users@lists.sourceforge.net Message-ID: [EMAIL PROTECTED] Content-Type: text/plain; format=flowed; charset=iso-8859-1; reply-type=original the only idea I have is that there might have been a problem during burning... did you verify the md5sum of the cd before writing? Regards, Alex - Original Message - 8 - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] resolver to quadrature converter
Steve White wrote: Jon, I'm the guy from the CNC Workshop that had the Yaskawa encoder documentation you needed for testing the resolver to quadrature conversion. I also had the Panasonic servo motors / drives and a lot of other junk for sale there. Have you looked at the AD650 (also from Analog Devices)? I've never used any, but the data sheet looks like it might have potential. Here's a (really long) link to the data sheet. The AD650 is easy to find on their web site too if this long link fails. http://www.analog.com/static/imported-files/data_sheets/AD650.pdf#xml=http://search.analog.com/search/pdfPainter.aspx?url=http://www.analog.com/static/imported-files/data_sheets/AD650.pdffterm=f/vfterm=f/vla=en We keep going around and around on this, and I keep trying to explain why ONE F-V converter won't work, the problem is encoder dither. If the encoder is dithering, then the F-V gets a significant rate of counts, and the direction is flipping back and forth at a high rate. This will drive a servo system crazy. One possibility is to use two carefully matched F-V converters into a opposite inputs of a differential amp. Feed positive encoder counts to one, negative counts to the other. The dither will just cancel out. I may have to mock this up and try it out. It may be better than a complicated digital fitering scheme, but it likely will have to be carefully adjusted on the bench. The digital scheme should have minimal adjustments. Jon - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] resolver to quadrature converter
Dave Engvall wrote: Hi Steve, Jon: The Analog Devices chips have really good specs especially at low freq. How they are rather pricey in todays world of inexpensive chips with excellent performance. A couple of $14 to $31 chips drives the price of the finished board up pretty fast. There is a National tach chip ( LM2917) at much lower prices but also lower specs. This is still a unipolar (= unidirectional) F-V converter. I wonder how well a digital approach with a simple moving average would work. I'm assuming that a good digital filter would take too much time to compute but that is someone else's problem. ;-) FPGAs can do digital filters in the MHz range, if you really need it. But, the problem is to filter a discontinuous-time signal (encoder counts) into an approximation of a continuous-time signal (velocity) with minimal delay AND minimal ripple at low speed. NOT trivial. Jon - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Tandem Axes-YY
Jon Elson wrote: Ray Henry wrote: Are there swivel joints between the two screws so that the motors can move independent of each other? Excellent point, and no, there do not appear to be any joints between the two sides. (Dr. Lie has sent me photos of the machine.) That is going to make it MUCH harder to properly home the thing without bending the rails or ballscrews. I wonder if it would work better to home one side, with the other side's servo amp disabled, and then home the second side the last few encoder counts. Or, home the system with the servo P gain turned WAY down, just high enough to get movement, and then turn it up after the axes are in sync. That solution assumes that one side can back drive the other. That isn't necessarily the case. It might be worth considering a home switch on just one side and a squareness indicator on the other side. (Somehow, measure the offset or flexing between the two screws.) Then drive one side to make the axis square. Then lock the two axes to each other and home the whole thing. This is, in general, a bad idea to have a rigid tandem axis. Jon - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users Ken - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Tandem Axes-YY
On Mon, 2008-07-14 at 13:02 -0400, Kenneth Lerman wrote: Jon Elson wrote: Ray Henry wrote: Are there swivel joints between the two screws so that the motors can move independent of each other? Excellent point, and no, there do not appear to be any joints between the two sides. (Dr. Lie has sent me photos of the machine.) That is going to make it MUCH harder to properly home the thing without bending the rails or ballscrews. I wonder if it would work better to home one side, with the other side's servo amp disabled, and then home the second side the last few encoder counts. Or, home the system with the servo P gain turned WAY down, just high enough to get movement, and then turn it up after the axes are in sync. That solution assumes that one side can back drive the other. That isn't necessarily the case. It might be worth considering a home switch on just one side and a squareness indicator on the other side. (Somehow, measure the offset or flexing between the two screws.) Then drive one side to make the axis square. Then lock the two axes to each other and home the whole thing. I'm thinking that it might be possible to measure the power to each of the two motors and work from that as a sort of squareness indicator. I can easily imagine a situation where one motor was constantly fighting the other across the beam connecting their leadscrews. The net effect would be to reduce the power available to move the beam. Or as John suggests reduce the gain to the second motor low enough so that it is moved when the first is homed, assume that it is also home and increase it's power to match the primary motor. After all, if they are both rigidly connected to the beam, what good does homing a second motor do. Rayh This is, in general, a bad idea to have a rigid tandem axis. - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] resolver to quadrature converter
On Mon, 14 Jul 2008, Jon Elson wrote: Date: Mon, 14 Jul 2008 11:33:37 -0500 From: Jon Elson [EMAIL PROTECTED] Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Subject: Re: [Emc-users] resolver to quadrature converter Dave Engvall wrote: Hi Steve, Jon: The Analog Devices chips have really good specs especially at low freq. How they are rather pricey in todays world of inexpensive chips with excellent performance. A couple of $14 to $31 chips drives the price of the finished board up pretty fast. There is a National tach chip ( LM2917) at much lower prices but also lower specs. This is still a unipolar (= unidirectional) F-V converter. I wonder how well a digital approach with a simple moving average would work. I'm assuming that a good digital filter would take too much time to compute but that is someone else's problem. ;-) FPGAs can do digital filters in the MHz range, if you really need it. But, the problem is to filter a discontinuous-time signal (encoder counts) into an approximation of a continuous-time signal (velocity) with minimal delay AND minimal ripple at low speed. NOT trivial. Jon A digital system that either did Count/TQuad velocity estimation, or 1/T velocity estimation at low speeds and switched to M/TSample at higher speeds is possibly a good way to go. Some fancier velocity estimators take higher order differences (and maybe motor applied torque) into account to get a better velocity estimate. If you go digital for processing, you still need to get a wide dynamic range, low delay signal out, which probably means a DAC, so its a multi chip solution. Our HostMot2 firmware supports Count/TQuad velocity estimation, basically just timestamping the quadrature edges, so that when you read the encoder counter you can read the number of counts that have occured and are able to accurately measure (well limited by quadrature phase distortion) the total time elapsed time for the counts. Some fancier stuff we've done for customers saved every timestamp in a FIFO so the differences could be extracted, and I've seen some other commercial hardware that saves the last 4 or 5 timestamps. A $2.50 DSPIC could probably do all this up to a few hundred KHz (I'd probably do the divide with a table) but you would need a SPI DAC to get the analog output... Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your ()_() signature to help him gain world domination. - Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] ac servo tuning
Jon Elson wrote: Terry wrote: Hi I have been trying to tune my ac drives using the method in the intergrators manual--Increase the p till oscillate then increase I till it stops This is very interesting to me as I recently purchased a small HMC with Fanuc AC amps and motors. Where can I find pinouts and specs on Fanuc equipment? The computer only has outputs for a maximum of 4 axis and I have plans to set it up for 5. Jon, can your Pico system drive such a thing? Thanks. Ed. - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100url=/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Tandem Axes-YY
Kenneth Lerman wrote: Jon Elson wrote: Ray Henry wrote: Are there swivel joints between the two screws so that the motors can move independent of each other? Excellent point, and no, there do not appear to be any joints between the two sides. (Dr. Lie has sent me photos of the machine.) That is going to make it MUCH harder to properly home the thing without bending the rails or ballscrews. I wonder if it would work better to home one side, with the other side's servo amp disabled, and then home the second side the last few encoder counts. Or, home the system with the servo P gain turned WAY down, just high enough to get movement, and then turn it up after the axes are in sync. That solution assumes that one side can back drive the other. That isn't necessarily the case. Right. I've seen pictures of the machine, it looks quite rigid, a welded steel box-tube frame with round slider ways bolted every 100 - 200 mm. A modestly robust gantry, although it looks like 80-20 extrusion plus several round ways between the two ends. It might be worth considering a home switch on just one side and a squareness indicator on the other side. (Somehow, measure the offset or flexing between the two screws.) Then drive one side to make the axis square. Then lock the two axes to each other and home the whole thing. Well, the problem is when the thing fires up, the two servo drives will be fighting each other and distorting the frame. It needs some scheme to keep the two drives from fighting against each other, even BEFORE the axes are homed. It is not real clear how you do this, especially since it is relatively rigid. How do you determine the flex in the frame? Strain gauges? Wire-spool encoders on each side? Absolute encoders? Actually, matching up absolute encoders sounds like a possible solution. Jon - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100url=/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Tandem Axes-YY
On Mon, 14 Jul 2008, John Kasunich wrote: Date: Mon, 14 Jul 2008 21:11:13 -0400 From: John Kasunich [EMAIL PROTECTED] Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Tandem Axes-YY Jon Elson wrote: I've seen pictures of the machine, it looks quite rigid, a welded steel box-tube frame with round slider ways bolted every 100 - 200 mm. A modestly robust gantry, although it looks like 80-20 extrusion plus several round ways between the two ends. It might be worth considering a home switch on just one side and a squareness indicator on the other side. (Somehow, measure the offset or flexing between the two screws.) Then drive one side to make the axis square. Then lock the two axes to each other and home the whole thing. Well, the problem is when the thing fires up, the two servo drives will be fighting each other and distorting the frame. It needs some scheme to keep the two drives from fighting against each other, even BEFORE the axes are homed. It is not real clear how you do this, especially since it is relatively rigid. How do you determine the flex in the frame? Strain gauges? Wire-spool encoders on each side? Absolute encoders? Actually, matching up absolute encoders sounds like a possible solution. Jon One approach is to consider the power-up state as acceptable meaning since the motors were free-wheeling a minute ago, there can't be too much stress in the machine. Record the offset between the two encoder feedbacks before enabling the amps, and maintain that offset while moving toward home. The gantry may be a bit out of square, but it won't get any worse. When one axis hits home, record the position and keep moving. When the other hits home, record its position and stop (still keeping the same offset between motors). Then use the two recorded positions to determine the exact offset between the encoders that will result in a square gantry. Then move one (or both) motors to that offset. Regards, John Kasunich - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100url=/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users A similar scheme if the startup condition is acceptable (enough for one turn of the motor), is to do the above scheme to move the motors one turn and locate the encoder index points, then use the measured offset between indexes to synchonize the axis (assuming the matched index means perfect mechanical alignment), then only one limit switch is needed Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your ()_() signature to help him gain world domination. - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100url=/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
