User manual
3U Servo Amplifier
Position Feedback and Polarity Test
If the PWM command values observed in the Watch window are not zero, set them to zero with the
command:
M102=0 M104=0 M107=0
The motor can be turned (or pushed) freely by hand now. As the motor is turned, monitor the M101 value
in the Watch window. Look for the following:
It should change as the motor is moved. •
•
•
•
It should count up in one direction, and count down in the other direction.
It should provide the expected number of counts in one revolution or linear distance increment.
As the motor is returned repeatedly to a reference position, it should report (approximately) the same
position value each time.
If these things do not happen, check the encoder/resolver operation, its connection to Turbo PMAC and
the Turbo PMAC decode variable I7mn0. Double-check that the sensor is powered. In addition, look at
the encoder waveforms with an oscilloscope.
If the direction of motion to be the positive direction is known, check this here. If the direction is
incorrect, invert it by changing I7mn0, usually from 7 to 3, or from 3 to 7. If the direction is not known,
change it later, but make another change at that time to maintain the proper commutation polarity match;
usually by exchanging two of the motor phase leads at the drive.
Note:
Because I100 has been set to 0, and I103 may not yet have been set properly, any
change of position will not be reflected in the motor position window.
PWM Output and ADC Input Connection
WARNING:
Make sure before applying any PWM commands to the drive and motor in this
fashion that the resulting current levels are within the continuous current rating of
both drive and motor.
First, enable the amp, then apply a very small positive command value to Phase A and a very small
negative command value to Phase B with the on-line commands:
M114=1 ; Enable amplifier
M102=I7000/50 M104=-I7000/50 M107=0 ; A pos, B neg, C zero
This provides a command at 2% of full voltage into the motor; this should be well within the continuous
current rating of both drive and motor. It is a good idea to make the sum of these commands equal to zero
so as not to put a net DC voltage on the motor; putting all three commands on one line causes the changes
to happen virtually instantaneously.
With power applied to the drive and the amplifier enabled (M114=1), current readings should be received
in the ADC registers as shown by the M-Variables M105 and M106 in the Watch window.
Since the M-Variables are defined as +/-32,768 for full current range, which should correspond
approximately to the instantaneous current limit. Make sure that the value read does not exceed the
continuous current limit, usually which is about 1/3 of the instantaneous limit. If well below the
continuous current limit, increase the voltage command to 5% to 10% of maximum. For example:
M102=I7000/10 M104=-I7000/10 M107=0 ; 10% of maximum
Controller Setup 34