John K Thank you for your reply. Snips from two messages:
> You said: > > > I set the feed rate low, I can jog > > the X axis full travel > > And you also said: > > > Axis doesn't indicate > > any change of position, XYZ always remain zero. > > Does that mean you can make the machine physically move, without the > Axis display showing that movement? > Yes. > Physical movement (of any kind, including turning a shaft by hand while > the motors are powered down), must be detected by the encoders and > reported back to EMC, or your system just isn't gonna work. I know > everybody does things their own way, but if I was working on a system > that uses encoders, the very first thing I would do is make sure the > entire feedback path works. That would be long before I ever tried to > jog the machine. > Sounds sensible, but I don't know how to verify the feedback path short of actually running the machine. > Load the HAL files (with or without EMC), make sure the motors are > safely disabled (power disconnected or turned off), and turn the motor > shaft by hand. If the Axis display doesn't change, your feedback is > busted, and you MUST fix that before you do anything else. > Point taken. In my mind, the fact that the Axis display didn't change wasn't necessarily proof that the feedback was busted. > Put a halmeter on the encoder counts signal, turn the shaft again. If > the halmeter changes but Axis doesn't, then the encoder signals are > getting to the driver and being counted, but not getting to EMC, so > check the HAL config. (You can follow the signals thru the system using > the halmeter.) If the halmeter doesn't change when you turn the motor, > then either the hardware is broken, something isn't wired right, or the > driver is misconfigured. Time to get out the real multimeter or scope > and check the encoder power supply, signals, etc. > This is helpful. I had wired encoder connections incorrectly. I don't know the difference between ENCA0 and /ENCA0 pins on the M7i33 board. Connecting to /ENCA0 etc. worked. Scale and polarity correct. Axis now reads table and quill movement correctly (driven by hand). However, I still get joint following errors when jogging. I have tried to verify DAC outputs as described on your wiki page, but I've not grasped how to connect a HAL signal to the DAC outputs. If this is the right way to proceed, perhaps you would be kind enough to guide me through it? > Of course, all of this is based on your statement that you can slowly > jog X and Axis shows no movement. I may be totally misinterpreting your > words. SPEAK PRECISELY PEOPLE!! Sorry to shout, but that is a pet > peeve of mine. I get it in my day job too - people ask me to figure out > what is wrong with something, but their description of the symptoms is > so vague that its hopeless. Apologies if you didn't find it clear, it was not my intention to cause aggravation. > Here is a wiki page where I started to write down step-by-step the > process I would use for setting up a servo system. > > http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Tuning_EMC2/HAL_PID_Loops > > Very helpful. I would be pleased to see practical examples of using HAL to work through system problem solving. > I strongly suggest that you UNDERSTAND and follow at least the first > four steps. > > Someday I should finish that page... but on the other hand it could > be dangerous. I strongly believe that when working with a servo system, > you should understand exactly what you are doing and why. Simply > following a step-by-step recipe is NOT good if you don't really know > what you are doing. That leads to crashed machines or worse. The key > to success is understanding how the thing is supposed to work, so when > some step doesn't give the expected results you say "hmm, that doesn't > seem right, better look into it" instead of just moving on to the next step. > You make important points here. I am confident with the fundamental working of my old servo system, but more importantly, the response of the servos to designed inputs (together with the effect of the occasional catastrophic board failure!). I've had many years of using (and repairing) this mill. I find EMC is a steep learning curve, I am therefore, very grateful for your support. Regards, Richard ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
