Stability; Operation - Galil Motion Control DMC-18 2 Series User Manual

Using DMC Smart Terminal,
DMCDOS, or WSDK cannot
communicate with the controller.

Stability

SYMPTOM
Motor runs away when the loop is
closed.
Motor oscillates.

Operation

SYMPTOM
Controller rejects command.
Responded with a ?
Motor does not start or complete a
move.
During a periodic operation, motor
drifts slowly.
Same as above.
154 ● Chapter 9 Troubleshooting
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Plug and Play installation did not
proceed properly
CAUSE
Wrong feedback polarity.
(Positive Feedback)
Too high gain or too little
damping.
CAUSE
Anything.
Noise on limit switches stops the
motor. Noise on the abort line
aborts the motion.
Encoder noise
Programming error.
Check first that Dmc1802.INF was
used to install the controller. Next
check the controller registry to see
if the controller was automatically
added and an address selected.
REMEDY
Invert the polarity of the loop by
inverting the motor leads (brush type)
or the encoder (channel A+, B+ if
single ended; channel A+, A- if
differential)
Decrease KI and KP. Increase KD.
REMEDY
Interrogate the cause with TC or
TC1.
To check the cause, interrogate the
stop code (SC). If caused by limit
switch or abort line noise, reduce
noise.
Interrogate the position
periodically. If controller states
that the position is the same at
different locations it implies
encoder noise. Also use a scope to
see the noise. Reduce noise. Use
differential encoder inputs.
Avoid resetting position error at
end of move with SH command.
DMC-18x2