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Rockwell Automation Publication 1769-UM021G-EN-P - October 2015
Chapter 7
Use I/O Modules with CompactLogix 5370 L1 Controllers
Module Faults Related to RPI Estimates
When following the guidelines described on
, most
CompactLogix 5370 L1 control systems operate as expected.
Some systems that follow the guidelines can experience minor faults that are
described in the following table.
Calculate System Power Consumption
An embedded 24V DC nominal, non-isolated power supply with an input range
of 10…28.8V DC powers the CompactLogix 5370 L1 control system.
The embedded power supply provides 1 A @ 5V DC to the POINTBus
backplane to power all system components, including local expansion modules,
that is 1734 POINT I/O modules, in most system configurations.
In some circumstances, you can configure a system that requires more current
than the embedded power supply of the system provides. This type of
configuration results from using a combination of local expansion modules that,
when combined with current consumption of the rest of the system, exceeds
1 A @ 5V DC.
Name
Fault
Information
Condition In Which Fault Occurs
Module
RPI
Overlap
(Type 03) I/O fault
(Code 94) Module
RPI overlap
detected
Module Slot =
x
,
where
x
is the slot
number of the I/O
module in the I/O
Configuration
section
This fault is logged when the current RPI update of an I/O module overlaps with its
previous RPI update. The Minor Faults tab in the Controller Properties dialog box
indicates which module the RPI overlaps.
If multiple I/O modules experience the fault, the application indicates that the fault
occurred on the first such I/O module. Typically, it is an I/O module with a lower RPI
rate and/or an I/O module with large input/output data sizes. For example, the
1734-232ASC and 1734-485ASC modules use large input/output data sizes.
Once the fault is cleared from the first I/O module, the application indicates the
next module that experiences the fault. This pattern continues until the fault is
cleared from all affected I/O modules.
To avoid this fault, set the RPI rate of the I/O modules to a higher numerical value.
