Allen-Bradley ControlLogix 1756-DH485, User Manual, Page: 97 / 110

1 Publication 1756-UM532A-EN-P - May 2006
Appendix
B
Troubleshoot the 1756-DH485 Module
Introduction
This chapter describes diagnostics and methods of troubleshooting the
module.
Check Power Supply and
Module Status
When you apply power to the module, three events take place simultaneously.
Alphanumeric status indicator on the module illuminates and cycles through
the following sequence of messages:
– INIT
– Channel A and the network used for channel A
– Channel A node address
– Channel A status
– Channel B and the network used for channel B
– Channel B node address
– Channel B status
This channel sequences run continuously during normal module
operation.
Module OK status indicator flashes red, then goes solid green.
For See
Check Power Supply and Module Status B-1
Interpret the LED Status Indicators B-2
Interpret the Alphanumeric Indicators B-3
Interpret the OK Status Indicator B-4
Routing Errors in DH-485 Messaging B-4
EXAMPLE
For example, if your module uses the following:
•
Channel A for DH485 with node address 14
•
Channel B for DH485 with node address 0, but being
the only node on the network.
•
A DH, A#14, A OK, B DH, B#0, ONLY NODE