Rockwell Automation 61C351 2-In/2-Out 4-20 mA Analog Rail Module - Manual (Page 37)

5Ć3
5.2 TheCOM OK" LED is Off
Problem: The COM OK" LED on the faceplate is off. This LED
signifies whether there is communication between the Analog Rail
and the host. The LED should be on if communication is taking
place. The possible causes of this problem are incorrect
configuration, a disconnected or malfunctioning I/O Rail cable, a
malfunctioning host, or a malfunctioning Analog Rail module. After
verifying that the configuration of the Analog Rail is correct, follow
the steps below to isolate the problem.
Step 1.
Stop any application tasks or programs that are running
and turn off power to the Analog Rail module.
DANGER
VOLTAGE IS PRESENT ON THE PLUG CONNECTOR TERMINALS. DISCONNECT
THE POWER AT THE SOURCE BEFORE TOUCHING THE PLUG CONNECTOR
TERMINALS. FAILURE TO OBSERVE THIS PRECAUTION COULD RESULT IN
SEVERE BODILY INJURY OR LOSS OF LIFE.
DANGER
DO NOT TOUCH THE CONNECTORS ON THE FACEPLATE IF THERE IS POWER
ON THE WIRES ATTACHED TO THE PLUG CONNECTOR SCREW TERMINALS.
ALWAYS TURN OFF POWER BEFORE HANDLING A CONNECTOR THAT IS
WIRED. FAILURE TO OBSERVE THIS PRECAUTION COULD RESULT IN SEVERE
BODILY INJURY OR LOSS OF LIFE.
Step 2. Verify that the connections on both ends of the I/O Rail
cable are tight. Check that the pins on the input
connector are not bent.
Step 3. Turn on power to the module. The COM OK" LED should
be illuminated if communication is taking place. If the LED
still does not illuminate, turn off power to the module and
replace the I/O Rail cable.
Step 4. If applicable, try to reset the condition by disconnecting
and then reĆconnecting the cable between the host and
the Local I/O Head, the AutoMate Remote I/O Head, or
the DCS 5000/AutoMax Remote I/O Head. Troubleshoot
the host if necessary. If the problem is still not corrected,
replace the Analog Rail module.
5.3 Incorrect Data
Problem: The data (signal) being read or written is always on,
always off, or different than expected. The possible causes of this
problem are incorrect configuration, a programming error, a
disconnected or malfunctioning I/O Rail cable, disconnected or
malfunctioning wiring to the external hardware, malfunctioning
external hardware or a malfunctioning Analog Rail module. After
verifying that the configuration of the module is correct, follow the
steps below to isolate the problem.
Step 1.
Verify that the application program(s) is correct. Check to
see that the program is referencing the correct registers
(AutoMate) or symbolicnames (DCS 5000/AutoMax).