> > > > The comment on the link about Ethernet latency is what interested me. > > Again if electrical noise causes retries or delays in the Ethernet > > signalling then that could cause this sort of error under heavy load. > > > > John > > And this is what the high frequency gains do, FF2 and Dgain, giving a > boost when the velocity changes. All this assumes that the actual power > available is sufficient to achieve what the controller is asked to make > it do. If the available power sags with the initial accell but the speed > being asked is so high the power available cannot catch it up and is > limiting you then following errors creep into long distance moves. > Hi Gene, My AC Servo is run open loop with step/dir. It's not the Servo Driver that is calling out a following error. It's LinuxCNC that also has no clue where the motor actually is unless the AC servo asserts a fault output. And it can't do that because I disconnected it for this test.
I don't know how the Ethernet Communications with the MESA 7i92H works. Page 8 of the user manual says it's UDP which means launch and forget. The sender has no way of knowing if the message was received although with only two devices perhaps there's a lower level that does verify that. In either case Page 31 states there are error counters so if there is a packet error that is detected after a new motion command is issued; like change direction for example. Then LinuxCNC might well decide to throw up a following error. I will admit that I misread the HAL instructions and had the MAX_ACCELERATION parameter set to 125% higher. But with Backlash it was supposed to be 200%. Once I changed that the problem went away. So bad HAL info generates a following error? Except that never happened without the extra 92 lbs on the table. But if electrical noise from the higher load did cause a damaged UDP packet then there's the answer. A quick change in direction to handle backlash and a missing message throws out the timing and results in a following error. John _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
