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Chapter 2. Troubleshooting
29
Common Problems & Solutions
NOTE
Some software-related causes are provided because it is
sometimes difficult to identify a problem as either
hardware or software related.
Problem Cause Solution
Communication
(serial) not operative,
or receive garbled
characters.
1. Improper interface connections or
communication protocol.
2. Serial communication is disabled.
3. In a daisy chain, the unit may not be
set to proper address.
1. See
Troubleshooting Serial Communication
section below.
2. Enable serial communication with the E1 command.
3. Verify DIP switch settings (see page 6), or proper use of ADDR command.
Direction is reversed.
(stable servo
response)
1. Command output (CMD) connections
and feedback device connections or
mounting are reversed.
1. Hardware remedy: Switch CMD- with the CMD+ connection to the drive
(if your drive does not accept differential outputs this will not work). You will
also have to change the feedback device wiring or mounting so that it counts in
same direction as the commanded direction.
Direction is reversed.
(unstable servo
response)
1. Not tuned properly.
2. Phase of encoder reversed or
mounting of ANI input is such that it
counts in the opposite direction as the
commanded direction.
1. Refer to the tuning instructions in the
Servo Tuner User Guide
or in
Appendix A.
2. If encoder feedback, swap the A+ and A- connections to the OEM6250. If
ANI feedback, change the mounting so that the counting direction is reversed.
Distance, velocity, and
accel are incorrect as
programmed.
1. Incorrect encoder resolution setting. 1. Match the ERES command setting (default ERES setting is 4,000
counts/rev) to match the post-quadrature resolution of the encoder.
ERES values for Compumotor encoders:
E Series: ERES4000
SM Series Servo Motors:
SMxxxxD-xxxx: ERES2000
SMxxxxE-xxxx: ERES4000
OEM Series motors (servo):
OEM2300E05A-MO: ERES2000
OEM2303E05A-MO: ERES2000
OEM3400E05A-MO: ERES2000
OEM3401E10A-MO: ERES2000
OEM2300E05A-MO: ERES4000
OEM2303E10A-MO: ERES4000
OEM3400E10A-MO: ERES4000
OEM3401E10A-MO: ERES4000
OEM2300E20A-MO: ERES8000
OEM2303E20A-MO: ERES8000
OEM3400E20A-MO: ERES8000
OEM3401E20A-MO: ERES8000
Encoder counts
missing.
1. Improper wiring.
2. Encoder slipping.
3. Encoder too hot.
4. Electrical noise.
5. Encoder frequency too high.
1. Check wiring.
2. Check and tighten encoder coupling.
3. Reduce encoder temperature with heatsink, thermal insulator, etc.
4.a. Shield wiring.
4.b. Use encoder with differential outputs.
5. Peak encoder frequency must be below 1.6MHz post-quadrature. Peak
frequency must account for velocity ripple.
Erratic operation. 1. Electrical noise and/or improper
shielding.
2. Improper wiring.
1.a. Reduce electrical noise or move OEM6250 away from noise source.
1.b. Refer to
Reducing Electrical Noise
on page 28.
2. Check wiring for opens, shorts, & mis-wired connections.
LEDs See
Diagnostic LEDs
above (page 28)
Motion does not occur. 1. Check LEDs.
2. End-of-travel limits are active.
3. ENBL (enable) input not grounded.
4. Drive fault detected.
5. Improper wiring.
6. Load is jammed.
7. No torque from motor.
8. Max. allowable position error (SMPER
value) exceeded.
1. See
Diagnostic LEDs
above.
2.a. Hardware limit switches: Move load off of limits or disable limits with the
LH¯,¯ command.
2.b. Software limits: Set LSPOS to a value greater than LSNEG.
3. Ground the ENBL connection.
4.a. Check status with TASXF command (see bit #4).
4.b. Verify correct drive fault level setting (DRFLVL command value).
5. Check command (CMD), shutdown (SHTNC or SHTNO),
drive fault (DFT), and end-of-travel limit connections.
6. Remove power and clear jam.
7. See problem:
Torque, loss of
.
8. Check status with TASF report (see bit #23), and issue the DRIVE1
command to the affected axis.
Motion does not occur
in joystick mode.
1. Joystick Release input not grounded.
2. Improper wiring.
1. Ground Joystick Release input.
2. Check wiring for opens, shorts, and mis-wired connections.