Rockwell Automation 1762-Lxxxx MicroLogix 1200 Programmable Controllers - Manual (Page 124)

Publication 1762-UM001G-EN-P - March 2011
C-4 Troubleshoot Your System
Analog Expansion I/O
Diagnostics and
Troubleshooting Module Operation and Channel Operation
The module performs operations at two levels:
• module level
• channel level
Module-level operations include functions such as power-up, configuration,
and communication with the controller.
Internal diagnostics are performed at both levels of operation. Both module
hardware and channel configuration error conditions are reported to the
controller. Channel over-range or under-range conditions are reported in the
module’s input data table. Module hardware errors are reported in the
controller’s I/O status file. Refer to the MicroLogix 1200 and 1500
Programmable Controllers Instruction Set Reference Manual, publication
1762-RM001 for more information.
When a fault condition is detected, the analog outputs are reset to zero.
Power-up Diagnostics
At module power-up, a series of internal diagnostic tests are performed.
Table C.2 Module Status LED State Table
If module
status LED is Indicated
condition Corrective action
On Proper Operation No action required.
Off Module Fault Cycle power. If condition persists, replace the
module. Call your local distributor or
Allen-Bradley for assistance.