Rockwell Automation T7491 ICS Regent+Plus Mixed I/O Modules - Manual (Page 17)

Multiplexed I/O Module (T7491)
P D - 7 0 3 5 M a r - 0 6
17
Maintenance
No periodic maintenance or calibration is required for the
multiplexed I/O module. There are no user replaceable parts
inside the module.
Troubleshooting
Most problems with the Mux I/O equipment relates to
improper configuration. For correct operation you should
carefully check the protocol configuration (single vs. dual) and
the MIU processor addresses. Verify the configuration
information with the link settings for the MIU processors.
Also you should carefully check the serial cable connections.
The Mux I/O module labels the serial cable connections with
‘A’ and ‘B’ designations although the MIU processors refer to
the connections as ‘+’ and ‘-’. The serial cable connection
diagram in Figure 4 properly illustrates the relationship
between these signal references.
Safety Considerations
The Multiplexed I/O module is TÜV certified as non-
interfering and may be used for non-safety critical inputs and
outputs.
While the use of dual protocol configurations for 2oo2 voting
provides greater security for the communications link, it is not
sufficient to meet the requirements for Risk Class 5 safety
critical inputs and outputs. In applications of Mux I/O
equipment for maintenance override of safety critical inputs,
redundant Mux I/O Modules and MIU equipment is
recommended.
For additional safety considerations, please refer to the Safety
Considerations section of the Regent User’s Guide.