Rockwell Automation 57C419 5V-24V DC Input Module - Manual (Page 27)

5Ć3
5.2 Bus Error
Problem: A 31" or 51" through 58" appears on the Processor
module's LED. This error message indicates 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 the wrong 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 and that
the I/Odefinitions are correct.
Refer to figure 3.4. Verify that the slot number being
referenced agrees with the slot number defined in the
configuration task. Verify that the register number and bit
number are correct.
For remote I/Oinstallations, also verify that the master slot
and drop number are defined correctly.
Step 2. Verify that the module can be accessed.
Connect the programming terminal to the system and run
the ReSource Software. Use the I/O MONITOR to monitor
the four registers on the input module. If the I/O MONITOR
is able to monitor the inputs, the problem lies in the
application software (proceed to step 3). If the I/Omonitor
cannot monitor the inputs, the problem lies in the
hardware (proceed to step 4).
Step 3. Verify that the user application program is correct.
Registers 0 and 1 of the input module cannot be written to.
If a BASIC task caused the bus error, the error log will
contain the statement number in the task where the error
occurred. If a Ladder Logic or Control Block task caused
the error, you will need to search the task for any instances
where you used an input as a ladder logic coil or wrote to
it in a Control Block task.
Step 4. Verify that the hardware is working correctly.
Verify the hardware functionality by systematically
swapping out the input module, the Processor module(s)
and the backplane. After each swap, if the problem is not
corrected, replace the original item before swapping out
the next item.
To test the remote rack, connect a dumb terminal or a
personal computer running terminal emulation software
such as Kermit to the slave remote I/Omodule RSĆ232C
port. Set the port parameters on the terminal or computer
to 8 bits, 1 stop bit, no parity and a baud rate of 1200.
Connect the remote I/Omodule (C<CR> with Kermit).
See the Remote I/Oinstruction manual JĆ3606 for how to
test the module.
If you cannot determine the problem, replace the input
module. Next, replace the slave remote I/Omodule. If the
problem persists, take all of the modules out of the remote
backplane except the slave remote I/Omodule and the
input module. If the problem is now corrected, one of the
other modules in the rack is malfunctioning. Reconnect
the other modules one at a time until the problem