Rockwell Automation 57C428 Toledo Scale Interface Module - Manual (Page 29)

5Ć3
time until the problem reappears. If none of these tests
reveals the problem, replace the backplane.
5.3 Bus Error
Problem: A 31" or 51"Ć54" appear on the processor module`s
LED. These error messages indicate that there was a bus error when
the system attempted to access the module. The possible causes of
this error are a missing module, a module in the wrong slot, or a
malfunctioning module. It is also possible that the user is attempting
to write to readĆonly registers on the module. Use the following
procedure to isolate a bus error:
Step 1.
Verify that the input module is in the correct slot.
Refer to figure 3.3. Verify that the slot number being
referenced agrees with the slot number defined in the
configuration task. Verify that the register numbers that
have been assigned to the variables agree with the
definitions in the configuration task.
Step 2. Verify that the module can be accessed.
Connect the programmer to the system and run the
ReSource Software. Monitor register 14 on the module. If
the programmer is able to monitor it, the problem lies in
the application software (refer to step 3). If the
programmer cannot monitor the register, the problem lies
in the hardware (refer to step 4).
Step 3. Verify that the user application program is correct.
The error log will contain the number of the BASIC
program statement in which the error occurred. Verify that
any variables in a statement identified in the error log that
alter the contents of memory refer only to registers 20 thru
39. These are the only registers that can be written to by
an application task.
Step 4. Verify that the hardware is working correctly.
Systematically swap out the the interface module, the
Processor module (s), and the backplane. After each
swap, determine if the problem has been corrected before
swapping out the next item.