User manual

Geo Brick Drive User Manual
Motor Setup 202
Open-Loop Test, Encoder Decode: I7mn0
Having calculated the Slip Gain Ixx78 and performed a satisfactory current-loop tuning, an open-loop test
can now be performed to verify the direction sense of the encoder counting versus the command output.
A positive command should create a positive velocity and a position counting in the positive direction; a
negative command should create a negative velocity and a position counting in the negative direction.
Because of the slow acceleration nature of AC Induction motors, a manual open loop test might be more
practical than the automatic utility from the PMACTuningPro2 Software.
Manual Open-Loop Test: Issue a conservative open loop command from a terminal window (i.e. #4o10)
and monitor the velocity in the position window. The motor should rotate in the positive direction.
Similarly a negative open-loop command (#4o-10) should move the motor in the negative direction. If no
or very little motion is observed, increase the magnitude by increments of 10 (i.e. #4o20, #4o-20) to
obtain a conclusive result.
Automatic Open-Loop Test: In order to obtain good results using the automatic utility with AC
induction motors, the test magnitude and time are set to values which are larger than usual. This is due to
the slow rise time with most AC Induction Motors.
Examples:
Automatic Open-loop test magnitude of 20% with a test time of 300 msec showing good response and
correct encoder decode I7mn0 (I7040 for motor #4)