Galil Motion Control DMC-1000 User Manual page 33

14 • Chapter 2 Getting Started
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OE 1 <CR> Disables X axis amplifier when excess position error
exists
If the motor runs away and creates a position error of 2000 counts, the
motor amplifier will be disabled. Note: This function requires the
AEN signal to be connected from the controller to the amplifier.
Step C. Set Torque Limit as a Safety Precaution
To limit the maximum voltage signal to your amplifier, the DMC-1000
controller has a torque limit command, TL. This command sets the
maximum voltage output of the controller and can be used to avoid
excessive torque or speed when initially setting up a servo system.
When operating an amplifier in torque mode, the voltage output of the
controller will be directly related to the torque output of the motor.
The user is responsible for determining this relationship using the
documentation of the motor and amplifier. The torque limit can be set
to a value that will limit the motors output torque.
When operating an amplifier in velocity or voltage mode, the voltage
output of the controller will be directly related to the velocity of the
motor. The user is responsible for determining this relationship using
the documentation of the motor and amplifier. The torque limit can be
set to a value that will limit the speed of the motor.
For example, the following command will limit the output of the
controller to 1 volt on the X axis:
TL 1 <CR>
Note: Once the correct polarity of the feedback loop has been determined,
the torque limit should, in general, be increased to the default value of
9.99. The servo will not operate properly if the torque limit is below
the normal operating range. See description of TL in the command
reference.
Step D. Connect the Motor
Once the parameters have been set, connect the analog motor command
signal (ACMD) to the amplifier input.
To test the polarity of the feedback, command a move with the
instruction:
PR 1000 <CR> Position relative 1000 counts
BGX <CR> Begin motion on X axis
When the polarity of the feedback is wrong, the motor will attempt to
run away. The controller should disable the motor when the position
error exceeds 2000 counts. If the motor runs away, the polarity of the
loop must be inverted.
Note: Inverting the Loop Polarity
When the polarity of the feedback is incorrect, the user must invert the
loop polarity and this may be accomplished by several methods. If you
are driving a brush-type DC motor, the simplest way is to invert the
two motor wires (typically red and black). For example, switch the M1
and M2 connections going from your amplifier to the motor. When
driving a brushless motor, the polarity reversal may be done with the
encoder. If you are using a single-ended encoder, interchange the
DMC-1000