User manual

3U Servo Amplifier
PWM/ADC Phase Match
Command values from Turbo PMAC’s Phase A PWM outputs should cause a roughly proportionate
response of one sign or the other on Turbo PMAC’s Phase A ADC input (whatever the phase is named in
the motor and drive). The same is true for Phase B.
If no response is received on either phase, re-check the entire setup, including:
Is the drive properly wired to Turbo PMAC, either directly or through an interface board?
Is the motor properly connected to the drive?
Is the drive properly powered, both the power stage, and the input stage?
Is the interface board properly powered?
Is the amplifier enabled (M114=1 on Turbo PMAC and indicator ON at the drive)?
Is the amplifier in fault condition? If so, why?
If only an ADC response is received on one phase, the phase outputs and inputs may not be matched
properly. For example, the Phase B ADC may be reading current from the phase commanded by the
Phase C PWM output. Confirm this by trying other combinations of commands and checking which
ADC responds to which phase command. If there is not a proper match, change the wiring between
Turbo PMAC and the drive. Changing the wiring between drive and motor will not help here.
Synchronous Motor Stepper Action
With a synchronous motor, this command should cause the motor to lock into a position, at least weakly,
like a stepper motor. This action may be received temporarily on an induction motor, due to temporary
eddy currents created in the rotor. However, an induction motor will not keep a holding torque
indefinitely at the new location.
Current Loop Polarity Check
Observe the signs of the ADC register values in M105 and M106. These two values should be of
approximately the same magnitude, and must be of the opposite sign from each other. (Again, remember
that these readings may appear noisy. Observe the base value underneath the noise.) If M105 is positive
and M106 is negative, the sign of the PWM commands matches the sign of the ADC feedback values. In
this case, the Turbo PMAC phase angle parameter I172 must be set to a value greater than 1024 (1365 for
a 3-phase motor).
If M105 is negative and M106 is positive, the sign of the PWM commands is opposite that of the ADC
feedback values. In this case, I172 must be set to a value less than 1024 (683 for a 3-phase motor).
Make sure your I172 value is set properly before attempting to close the digital current loops on Turbo
PMAC. Otherwise positive feedback will occur, creating unstable current loops which could damage the
amplifier and/or motor.
If M105 and M106 have the same sign, the polarities of the current sense circuitry for the two phases is
not properly matched. In this case, something has been miswired in the drive or between Turbo PMAC
and the drive to give the two phase-current readings opposite polarity. One of the phases will have to be
fixed.
Do not attempt to close the digital current loops on Turbo PMAC until the polarities of the current sense
circuitry for the two phases have been properly matched. This will involve a hardware change in the
current sense wiring, the ADC circuitry, or the connection between them. As an extra protection against
error, make sure that Ixx57 and Ixx58 are set properly for I
2
T protection that will shut down the axis
quickly if there is saturation due to improper feedback polarity.
Troubleshooting
If not getting the current readings expected, probe the motor phase currents on the motor cables with a
snap-on hall-effect current sensor. If the current is not seen when commanding voltages, check for phase-
to-phase continuity and proper resistance when the motor is disconnected.
Controller Setup 35