User Manual

PID Tunings
Advanced Digital Motor Controller User Manual 169
Beware that the Destination Reached flag will become true when the result of the trajec-
tory computation equals the desired destination. In most practical situations, the motor
will still be on its way to actually reach that destination. This can be an important consid-
eration when chaining commands, as the new command will become active before the
motor has actually reached the previous destination
PID Tunings
As long as the motor assembly can physically reach the acceleration and velocity, smooth
motion will result in relatively little need for tuning. As for any position control loop, the
dominant PID parameter is the Proportional gain with only little Integral gain and smaller or
no Derivative gain. See “PID tuning in Position Mode”on page 148.
Loop Error Detection and Protection
The controller will detect large tracking errors due to mechanical or sensor failures, and
shut down the motor in case of problem in closed loop speed or position system. The
detection mechanism looks for the size of the tracking error (desired position vs. actual po-
sition) and the duration the error is present. Three levels of sensitivity are provided in the
controller configuration:
1: 250ms and Error > 100
2: 500ms and Error > 250
3: 1000ms and Error > 500
When an error is triggered, the motor channel is stopped until the error has disappeared,
the motor channel is reset to open loop mode. The error will also be cleared when send-
ing a new Position Destination using the !P command with value equal to actual position
(feedback).
The loop error can be monitored in real time using the Roborun PC utility.