Rockwell Automation 1769-BOOLEAN Compact I/O Module Reference Manual - Manual (Page 60)

Publication 1769-RM016A-EN-P - July 2006
60 Module Diagnostics and Troubleshooting
Program Alteration
There are several possible causes of alteration to the user program, including
extreme environmental conditions, Electromagnetic Interference (EMI),
improper grounding, improper wiring connections, and unauthorized
tampering. If you suspect a program has been altered, check it against a
previously saved program on an EEPROM or UVPROM memory module.
Safety Circuits
Circuits installed on the machine for safety reasons, like over-travel limit
switches, stop pushbuttons, and interlocks, should always be hard-wired to the
master control relay. These devices must be wired in series so that when any
one device opens, the master control relay is de-energized, thereby removing
power to the machine. Never alter these circuits to defeat their function.
Serious injury or machine damage could result.
Power Cycle Diagnostics When you cycle power to the module, a series of internal diagnostic tests are
performed. These diagnostic tests must be successfully completed or a module
error results and is reported to the controller.
Module Error Definition
Table Module errors are expressed in two fields as four-digit Hex format with the
most significant digit as don’t care and irrelevant. The two fields are Module
Error and Extended Error Information.
Module Error Table
Module Error Field
The purpose of the module error field is to classify module errors into three
distinct groups, as described in the table below. The type of error determines
what kind of information exists in the extended error information field. These
types of module errors are typically reported in the controller’s I/O status file.
Refer to your controller manual for details.
Don’t Care Bits Module Error Extended Error Information
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Hex Digit 4 Hex Digit 3 Hex Digit 2 Hex Digit 1