Re: [Emc-users] Cable recommendations for Mesa boards
On Thu, 2008-11-20 at 13:45 -0800, Peter C. Wallace wrote: Is it possible your STEP and DIR inputs have optocouplers returned to 5V?. This is known problem with the 5I20 (or any of our FPGA cards) outputs since they only swing 0 to 3.3V. I think this is the problem based upon page 45 of the IMS483 manual, Figures 7.7 and 7.8. here are a couple of solutions to this depending on how you are connected to your step motor drivers 1. If 3.3V drive is enough for the inputs, return the anode of the input Optocouplers to 3.3V instead of 5V (5I20 connector pin 49 jumper option) I don't think 3.3 Volts will be enough because the recommended R_series in Figure 7.7 is 0 ohms for 5 Volts, meaning there is either an existing series resistance inside the drive, or the optocoupler has a 5 Volt TTL input. 2. If 3.3V drive is not enough or its inconvenient to get 3.3V to the drive, set the step and direction outputs into OPEN_DRAIN mode so you get a 5V swing Eric, do this, and use the 5 Volts from pin 49 of P4 on the 5i20 as the opto supply (P1:4 on the IMS483). Set W3 on the 5i20 board to the 5 Volt position. I think this will make it work with any of your cables. Thanks, Matt - 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] Cable recommendations for Mesa boards
Matt, (and everyone else) Thanks, I think you are right. I won't get a chance to test it until Tuesday, but will let you know. Regards, Eric I don't think 3.3 Volts will be enough because the recommended R_series in Figure 7.7 is 0 ohms for 5 Volts, meaning there is either an existing series resistance inside the drive, or the optocoupler has a 5 Volt TTL input. Eric, do this, and use the 5 Volts from pin 49 of P4 on the 5i20 as the opto supply (P1:4 on the IMS483). Set W3 on the 5i20 board to the 5 Volt position. I think this will make it work with any of your cables. - 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] Cable recommendations for Mesa boards
Matt Shaver wrote: On Thu, 2008-11-20 at 13:45 -0800, Peter C. Wallace wrote: 2. If 3.3V drive is not enough or its inconvenient to get 3.3V to the drive, set the step and direction outputs into OPEN_DRAIN mode so you get a 5V swing Eric, do this, and use the 5 Volts from pin 49 of P4 on the 5i20 as the opto supply (P1:4 on the IMS483). Set W3 on the 5i20 board to the 5 Volt position. I think this will make it work with any of your cables. You can set any hostmot2 output pin to open drain like this: setp hm2_5i20.0.gpio.XXX.is_opendrain 1 There's an example near the bottom of configs/hostmot2/hm2.hal. Note that the name of GPIO HAL-pins recently changed in TRUNK. In 2.2, the XXX part of the name above is Connector.IONum. In TRUNK, it's just IONum. Other than that it's all the same. -- Sebastian Kuzminsky sudden wind it stole my hat and i went on chasing it -- Gogol Bordello - 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
[Emc-users] Cable recommendations for Mesa boards
Hi all, I am running into a small problem with dropped / excess steps using the m5i20 board and Hostmot2 driver. The problem appears to be with the 50 pin cable connecting the m5i20 with the TB. The quick form of my question is, are there any recommended cables / manufacturers of cables to use with the Mesa boards in the 18 to 24 range? The longer explanation is as follows: With the Hostmot2 driver and m5i20 board, the stepper signals come off the P4 connector, the farthest connector from the point where the cable exits the computer. One loses about 8 just exiting the computer, so with an 18 cable, there is only about 10 left to get to the TB. Due to the panel layout, I really need a 24 cable from this connector. I have tried several lengths of ribbon cable, and one rounded cable. The best performing cable is the 24 rounded (it ought to, it cost about $20). I need to run about 20 cycles the length of the X axis to lose a quarter turn of the motor (i.e. drifts towards the min limit). The 18 flat cable will lose it in about 4 cycles. The stepper motion starts to get rough with a 30 flat cable, and anything longer (I was testing with a 54 cable) is so unstable as to basically not work at all. One odd thing is that with the 18 flat and 24 rounded cables, only the X axis demonstrates this problem, if Y is having any problem, it is so small that I have so far not been able to detect it. Past the TBs I am using Belden low capacitance cables with individually twisted pairs, foil shield and drain, plus an overall shield to connect the stepper signals to the drives. This part appears to be working fine, as nothing changes if I swap things around past the TBs. Any ideas or recommendations? Thanks, Eric - 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] Cable recommendations for Mesa boards
Eric H. Johnson wrote: Hi all, I am running into a small problem with dropped / excess steps using the m5i20 board and Hostmot2 driver. The problem appears to be with the 50 pin cable connecting the m5i20 with the TB. The quick form of my question is, are there any recommended cables / manufacturers of cables to use with the Mesa boards in the 18 to 24 range? The longer explanation is as follows: With the Hostmot2 driver and m5i20 board, the stepper signals come off the P4 connector, the farthest connector from the point where the cable exits the computer. One loses about 8 just exiting the computer, so with an 18 cable, there is only about 10 left to get to the TB. Due to the panel layout, I really need a 24 cable from this connector. I have tried several lengths of ribbon cable, and one rounded cable. The best performing cable is the 24 rounded (it ought to, it cost about $20). I need to run about 20 cycles the length of the X axis to lose a quarter turn of the motor (i.e. drifts towards the min limit). The 18 flat cable will lose it in about 4 cycles. The stepper motion starts to get rough with a 30 flat cable, and anything longer (I was testing with a 54 cable) is so unstable as to basically not work at all. One odd thing is that with the 18 flat and 24 rounded cables, only the X axis demonstrates this problem, if Y is having any problem, it is so small that I have so far not been able to detect it. Past the TBs I am using Belden low capacitance cables with individually twisted pairs, foil shield and drain, plus an overall shield to connect the stepper signals to the drives. This part appears to be working fine, as nothing changes if I swap things around past the TBs. Any ideas or recommendations? Thanks, Eric What kind of stepper drives? In particular, I'm asking about the inputs. Optocouplers, or non-isolated? Do they have any filtering? For the cable, have you tried twisted ribbon cable? Like this: http://media.digikey.com/photos/3M%20Photos/1700^50%20(100SF).jpg Although that photo seems to show only a few inches of twisted cable between the straight sections, usually it is longer. I have a partial spool that I got surplus a while back, I think it is 18 of twist and then 2 of straight (you have to put the connectors on the straight part). Or maybe it is 16 of twist and 2 of straight, totaling 18 per segment. I have several cables that are either 3 or 4 segments long that I use in a test computer with a 5i20, and I haven't noticed any noise issues. If you have the IDC connectors, I could send you a 6 foot chunk of cable to try. To be honest, I think you are dealing with more than just a cable issue. Flat ribbon cable with grounds on every other pin is really pretty good stuff. And step-dir is not that demanding - we're not talking PCI or even ISA bus, we're talking about pulses that are typically multiple microseconds long. If your signals/grounding are so marginal that 20 of cable clobbers things, you need to look closer - hence my question about the driver inputs. 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
Re: [Emc-users] Cable recommendations for Mesa boards
Eric H. Johnson wrote: I am running into a small problem with dropped / excess steps using the m5i20 board and Hostmot2 driver. The problem appears to be with the 50 pin cable connecting the m5i20 with the TB. The quick form of my question is, are there any recommended cables / manufacturers of cables to use with the Mesa boards in the 18 to 24 range? The longer explanation is as follows: With the Hostmot2 driver and m5i20 board, the stepper signals come off the P4 connector, the farthest connector from the point where the cable exits the computer. One loses about 8 just exiting the computer, so with an 18 cable, there is only about 10 left to get to the TB. Due to the panel layout, I really need a 24 cable from this connector. I have tried several lengths of ribbon cable, and one rounded cable. The best performing cable is the 24 rounded (it ought to, it cost about $20). I need to run about 20 cycles the length of the X axis to lose a quarter turn of the motor (i.e. drifts towards the min limit). The 18 flat cable will lose it in about 4 cycles. The stepper motion starts to get rough with a 30 flat cable, and anything longer (I was testing with a 54 cable) is so unstable as to basically not work at all. One odd thing is that with the 18 flat and 24 rounded cables, only the X axis demonstrates this problem, if Y is having any problem, it is so small that I have so far not been able to detect it. Past the TBs I am using Belden low capacitance cables with individually twisted pairs, foil shield and drain, plus an overall shield to connect the stepper signals to the drives. This part appears to be working fine, as nothing changes if I swap things around past the TBs. Any ideas or recommendations? I doubt that the ribbon cable between the FPGA board and the amplifier daughterboard is the problem. Based on Peter's recommentation, I'm using 5' long flat ribbon cables. Each cable has just two connectors (none in the middle). One connects my 5i20 to my break-out-board for the steppers; the other connects the 5i20 to my 7i30 servo amp. This setup is totally reliable for me here, but maybe my test setup/environment isnt as difficult/noisy as what you're working on. Are you sure it's noise in the cable, rather than, say, stepper timings or something? (Every human being should be issued an oscilloscope at birth.) -- Sebastian Kuzminsky - 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] Cable recommendations for Mesa boards
On Thu, 20 Nov 2008, Eric H. Johnson wrote: Date: Thu, 20 Nov 2008 15:46:08 -0500 From: Eric H. Johnson [EMAIL PROTECTED] Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: 'Enhanced Machine Controller (EMC)' emc-users@lists.sourceforge.net Subject: [Emc-users] Cable recommendations for Mesa boards Hi all, I am running into a small problem with dropped / excess steps using the m5i20 board and Hostmot2 driver. The problem appears to be with the 50 pin cable connecting the m5i20 with the TB. The quick form of my question is, are there any recommended cables / manufacturers of cables to use with the Mesa boards in the 18 to 24 range? The longer explanation is as follows: With the Hostmot2 driver and m5i20 board, the stepper signals come off the P4 connector, the farthest connector from the point where the cable exits the computer. One loses about 8 just exiting the computer, so with an 18 cable, there is only about 10 left to get to the TB. Due to the panel layout, I really need a 24 cable from this connector. I have tried several lengths of ribbon cable, and one rounded cable. The best performing cable is the 24 rounded (it ought to, it cost about $20). I need to run about 20 cycles the length of the X axis to lose a quarter turn of the motor (i.e. drifts towards the min limit). The 18 flat cable will lose it in about 4 cycles. The stepper motion starts to get rough with a 30 flat cable, and anything longer (I was testing with a 54 cable) is so unstable as to basically not work at all. One odd thing is that with the 18 flat and 24 rounded cables, only the X axis demonstrates this problem, if Y is having any problem, it is so small that I have so far not been able to detect it. Past the TBs I am using Belden low capacitance cables with individually twisted pairs, foil shield and drain, plus an overall shield to connect the stepper signals to the drives. This part appears to be working fine, as nothing changes if I swap things around past the TBs. Any ideas or recommendations? Thanks, Eric I'm with John here, Some thing else is going on. Step and Dir inputs normally not high bandwidth, and I would not expect troubles with even 10 foot flat cables. Is it possible your STEP and DIR inputs have optocouplers returned to 5V?. This is known problem with the 5I20 (or any of our FPGA cards) outputs since they only swing 0 to 3.3V. here are a couple of solutions to this depending on how you are connected to your step motor drivers 1. If 3.3V drive is enough for the inputs, return the anode of the input Optocouplers to 3.3V instead of 5V (5I20 connector pin 49 jumper option) 2. If 3.3V drive is not enough or its inconvenient to get 3.3V to the drive, set the step and direction outputs into OPEN_DRAIN mode so you get a 5V swing 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
Re: [Emc-users] Cable recommendations for Mesa boards
John, Sebastian and Peter, Here is a combined reply, using John's post as the basis. What kind of stepper drives? In particular, I'm asking about the inputs. Optocouplers, or non-isolated? Do they have any filtering? I am using an IM483 micro-stepping driver, the manual can be found here: http://imshome.com/Product%20Manual%20PDF/im483.pdf It has opto-isolated inputs (see page 43) for step, direction and enable, which are the only inputs I am using. The full list of I/O assignments are on pages 12 13. For the cable, have you tried twisted ribbon cable? Like this: http://media.digikey.com/photos/3M%20Photos/1700^50%20(100SF).jpg I was not able to find that in pre-made lengths, I could only find flat and rounded so I went with rounded like this (first one): http://www.pc-pitstop.com/scsi_cables/rounded_scsi_cables.asp Although that photo seems to show only a few inches of twisted cable between the straight sections, usually it is longer. I have a partial spool that I got surplus a while back, I think it is 18 of twist and then 2 of straight (you have to put the connectors on the straight part). Or maybe it is 16 of twist and 2 of straight, totaling 18 per segment. I have several cables that are either 3 or 4 segments long that I use in a test computer with a 5i20, and I haven't noticed any noise issues. If you have the IDC connectors, I could send you a 6 foot chunk of cable to try. Yea, I am familiar with it, I was just trying avoid making my own cables. I don't do it very often, so I invariably have to do it a few times to get a good cable, lined up properly and with good connections on every pin. I appreciate the offer, but I will just order a spool and some connectors, and do it myself if that is what it takes. To be honest, I think you are dealing with more than just a cable issue. Flat ribbon cable with grounds on every other pin is really pretty good stuff. And step-dir is not that demanding - we're not talking PCI or even ISA bus, we're talking about pulses that are typically multiple microseconds long. If your signals/grounding are so marginal that 20 of cable clobbers things, you need to look closer - hence my question about the driver inputs. It is really surprising in that this is the second machine and the first basically worked on the first go. They are both retrofits. The part from stepper drivers through to the motors is unchanged, while everything from the computer up to the stepper drivers has been replaced. I did encounter this at one point on the first system, but it went away when I swapped computers (and possibly cables). I was under a lot of pressure to get that system into production, so I never had the chance to trouble shoot it. However, as I had previously reported to Sebastian, it is working very well. The previous system had some real problems with arcs and generated a lot of jaggies. Under EMC, the jaggies are gone. From Sebastian: Are you sure it's noise in the cable, rather than, say, stepper timings or something? (Every human being should be issued an oscilloscope at birth.) I have not put a scope on it. My only speculation was that the cable was deforming the stepper square wave enough to cause occasional lost steps. From Peter: Is it possible your STEP and DIR inputs have optocouplers returned to 5V?. This is known problem with the 5I20 (or any of our FPGA cards) outputs since they only swing 0 to 3.3V. Hmm, maybe a little RTFM time is in order. I wired it up the same as the previous system, which used 5V rather than 3.3. Since the first system worked, I never checked. Thanks, Eric - 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
