Bruce Klawiter wrote: > > >> My understanding from a message about a week ago was that >> you had disconnected the DAC board from the Z axis amp, and >> still saw a twitch on the Z at the same time as the X twitched. >> > > I must have not have been very clear on that, what I said or meant to say is, > I disconnected the Z and Y axis from the DAC and disconnected all the > connectors from the Y and Z amps. With the Y and Z axis disconnected the X > axis still twitches. > I have disconnected the X axis and the Y and Z still twitch. > To ME, "disconnect" means removing wires. Do you mean you removed the HAL net command lines in one of the config files? That really does not do much, the driver is still writing the last value, or zero, to the DAC channel, every servo cycle. > If all the axes are connected and I run any one axis I get the twitching on > all the axes, 99% of the time. Once in a blue moon one axis will twitch by > itself, if that means anything. > > I did just unplug the Z axis from the DAC and the twitching went away on the > Z axis. > OK, so unplug is physical, and "disconnect" is software, is that right? If so, this now indicates the completely opposite situation. It might still be a ground loop, but is looking more and more like there is a communication error between the PPMC and the computer. There is a DAC communication test, but it can give misleading results, that's why I did not mention it before. Can you run the ppmcdiags with the "dactest" option, otherwise exactly the same as the commtest and other options? If you get error messages it may not mean a lot, as the DAC is normally a write-only device, and the test writes and reads back the values. Writing has always been fine, but reading back has some timing problems and so gives errors on some parallel ports. Errors in reading back won't affect the motion system, but the test can't distinguish between write errors and read errors.
Oh, VERY IMPORTANT, do not have the servo amps enabled when running this test! It writes random values to the DAC, and would drive the servos wild. If this doesn't turn up any useful info, then you may have to find a friend with an oscilloscope to check if there are pulses coming out of the DAC analog outputs. If there are such pulses, then we will have to find out what is causing them. Jon ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity and more. Splunk takes this data and makes sense of it. Business sense. IT sense. Common sense. http://p.sf.net/sfu/splunk-d2d-oct _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
