Rockwell Automation 1747-L5xx SLC 500 Modular Hardware Style User Manual - Manual (Page 126)

Publication 1747-UM011G-EN-P - June 2008
126 Starting Up Your Control System
Input Troubleshooting Steps
1. Make sure the processor is in the Continuous Scan Test mode.
2. If associated bit status and status indicator status do not match
the input device status, check status file S:11 and S:12 I/O slot
enables. Bits S:11/0 through S:11/15 and S:12/0 through S:12/14
should all be 1, enabling all I/O slots for the modular system.
3. Verify proper control power to the input device.
4. Remove the input device power and make sure circuit
terminations are properly wired and tightened.
5. Re-energize the input device power, and check for proper
control voltage between the input terminal and signal common
terminal.
6. If proper input control voltage does not exist, first check
minimum signal common by verifying voltage between input
device power source and the input common terminal.
7. If proper input voltage does exist, first check the minimum input
current specification on the input module, and then measure the
current in the input circuit. Replace the input module if
necessary.
8. If the input modules are OK, and proper voltage is measured
between input device source and input module common
terminal, test the input device and replace if necessary.
For more information on input troubleshooting see page 164.
5. Test Your Outputs After you test all inputs, and have determined that they are
functioning properly, test the outputs.
1. Refer to page 122 to insure no motion will occur when any controller
output is energized.
2. Place the controller in the Program mode.