Rockwell Automation 1746-XXXX SLC 500 4-Channel Analog I/O Modules User Manual - Manual (Page 57)

Publication 1746-UM005B-EN-P - June 2004
Testing Your Module 5-3
In some instances, you may not be able to disconnect a device the
preferred way. In these cases, open the output circuit at a point as
close as possible to the motion-causing device. For example, your
output might be a relay coil which in turn energizes a motor starter. If
you cannot disconnect the motor wires, open the circuit at a point
between the motor starter and the relay contact.
Power Up the SLC 500 System
Apply power to the fixed or modular system. The analog module LED
(red) should be illuminated, indicating that the module is receiving
24V dc power.
While an illuminated analog module LED does not ensure that the
module is operating properly, a non-illuminated LED indicates that the
analog module is not functional. Do not continue with the test
procedures until the LED is illuminated.
The four most probable causes of a non-illuminated LED are:
•
The SLC 500 system is not receiving power from its power
supply. Check the POWER LED on the fixed system unit or the
power supply on the modular system. If the LED is not
illuminated, refer to the Fixed Hardware Style Installation &
Operation Manual (publication 1747-6.21) or the Modular
Hardware Style User Manual (publication 1747-UM011). If the
module is a 1746-NO4I or NO4V, check the state of the optional
24V dc power switch. If external power is selected, but not
connected to the front of the module, the power LED will not
illuminate.
•
The power from the supply is not being received by the
remainder of the SLC 500 system. You can test this by attempting
to go online with the programming device.
•
The slot in the chassis where the analog module is located is not
operational. Remove the power from the SLC 500 system, move
the analog module to another slot and restore power. If it
appears that the slot is defective, replace the chassis.
•
The analog module is defective.
ATTENTION
Machine motion during system checkout can be
hazardous to personnel. During all checkout
procedures, you must disconnect all devices which,
when energized, might cause machine motion.