John Kasunich wrote: > > I guess I must have missed something. I never saw him say he was using > drives with step/dir inputs. Gecko G320 > If that is the case, then he probably > isn't > using PID loops at all - the drives are closing the position loop and > LinuxCNC is treating them like steppers. > > But, he is. This is using my Universal Stepper Controller with the Gecko Interface so it sees the encoder both places (drives and USC). So, it is truly a servo, although a messy one. The G320 has its own loop, and then LinuxCNC has another loop. You can turn down the Gecko gain and then do most of the positioning loop in LinuxCNC, and let the Gecko drive handle most of the velocity control. In some setups, especially with low DC voltage and high armature resistance, the G320 doesn't have anywhere enough P gain, so the LinuxCNC PID can help considerably to reduce following error.
But, still, if the encoder fails, there are many cases where LinuxCNC will not see a following error and not know there is a problem. Jon ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
