Rockwell Automation 1746-NO8V SLC 500 8-Point Analog Output Module/ User Manual - Manual (Page 54)

Publication 1746-UM026A-EN-P - September 2003
6-2 Module Diagnostics and Troubleshooting
Disconnecting Prime
Movers Before testing your module, ensure that machine motion will not
occur:
•
Disconnect motor wires at the motor starter or the motor itself.
This allows you to test the operation of the starter coil, verifying
that the output circuit is wired correctly and functioning.
•
Disconnect solenoids by disengaging the solenoid valves,
leaving the coils connected.
If you cannot disconnect a device in the preferred way, open the
output circuit as close as possible to the motion-causing device.
Power-Up Diagnostics When you apply power to the system, the module’s LEDs should
illuminate, indicating that your module is receiving power and has
completed its internal diagnostic self-test. If the LEDs do not
illuminate after several seconds, the module is not functional.
Discontinue testing until you can get the LEDs to illuminate.
The most probable reasons for the LED not illuminating are:
•
The SLC 500 system is not receiving power from its power
supply.
•
The rest of the SLC 500 system is not receiving power.
•
The chassis slot where your module is located is defective.
•
The analog module is defective.
EXAMPLE
If you have a relay coil that, in turn, energizes a
motor starter and you cannot disconnect the motor
wires, open the circuit at a point between the motor
starter and the relay contact.
WARNING
!
POSSIBLE UNEXPECTED MACHINE MOTION
During all testing, always disconnect all devices that,
when energized, might cause machine motion.
Failure to observe this precaution may cause
equipment damage or personal injury.
TIP
If the module is configured to use an external 24V dc
power supply, the supply must be turned on for the
module to operate. If the external 24V dc supply is
turned off, the module’s outputs will be turned off,
and the module’s processor will be reset until power
is restored.