Igor Chudov wrote: > > I do think that the motor is underpowered for the axis, if I had to move the > axis continuously. However, if I only need to use it occasionally to adjust > for tool height changes, it is OK. > Right, I understand what you WANT to do, and it does make some sense, but EMC is not designed to operate an axis in this manner. You want to completely break the normal way of doing things. > What is the issue that you are pointing out, is that when the axis is "at > rest", it is not really at rest from EMC2's standpoint, and its pid just > keeps applying the same logic as during the moves. > Yes, exactly, that is the normal design for an axis. > So, if I can find some way around that, I will be golden. > I really think it is a bad idea, as the position will be uncontrolled when not moving. > > The better news is that based on limited post-change testing that I did (I > was very tired by then at midnight), these changed in P and I, do work > better as far as bringing the ppmc.0.DAC.03.value down after a while. > > The motor does succeed at getting f-error very low (think 0.00007), and the > output of the motor controller becomes several times lower than in the past. > It settles down kind of slowly, over several seconds. > > That is the I term working as it should, it keeps creeping until it finally nulls out the error. Well, the real question is does the motor still overheat? If not, you are done. Maybe strap a safety thermostat to the motor to cause an estop if some time in the future it does run hot again. > I know that my drive is in torque mode (controls current), and the current > is about 10 times ppmc.0.DAC.03.value, per ammeter. So I can > watch ppmc.0.DAC.03.value and I will know what the current is. I am pretty > sure that the motor will not overheat from, say, 1 amp. > No, even a small motor should be OK. Assuming a rotten motor with 1 Ohm resistance, that will only dissipate one Watt with a 1 Amp idling current. Those crummy Ametek motors with 4 Ohm resistance would dissipate 16 W, which might still be in the safe area, but would get pretty warm.
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