SPRING 1184087 - Caterpillar

Test Procedure
System Operation
The SLC 5/04 - 5/05 diagnostic indicators are located on the front of the following components: Power Supply, CPU and I/O Modules.The processor detects the loss of power to any chassis in the system. When power is lost, the "FLT" LED illuminates. When power is lost, all of the outputs of the controller are de-energized. A loss of power to the expansion chassis will cause a fault of the processor. This is due to a loss of communication. A loss of power to the primary chassis extinguishes the LED.When the "FLT" LED is illuminated, there is a fatal error. A fatal error normally means that the processor is not communicating with modules in one or more of the chassis.
Illustration 1 g00766221
Diagram of the LED indicators
Illustration 2 g00766223
Functional Test
Check the electrical connectors and check the wiring.
Bodily contact with electrical potential can cause bodily injury or death.To avoid the possibility of injury or death, ensure that the main power supply has been disconnected before performing any maintenance or removing any modules.
Disconnect the power supply.
Check the electrical connectors and check the wiring for damage or bad connections.
Verify that all modules are properly seated.
Connect the power supply.
Verify the status of the LED on the SLC 542/552.The results of the preceding procedure are in the following list:
All of the components are fully installed. All of the components are free of corrosion. All of the components are free of damage. All of the modules are properly seated. Proceed to 2.
The components are not fully installed. The components are not free of corrosion. The components are damaged. All of the modules are not properly seated. Repair the component. Verify that the repair resolves the problem. STOP.
Check the line voltage.
Reconnect the power supply.
Measure the line voltage at the terminals.
Verify the voltage of the power supply. The power supply voltage should be measured between 21.0 VDC and 28.0 VDC.The results of the preceding procedure are in the following list:
The line voltage is in the range. Proceed to 3.
The line voltage is out of the range. Refer to Maintenance Procedure, "Power Supply - Replace".
Check for an overloaded power supply.
Bodily contact with electrical potential can cause bodily injury or death.To avoid the possibility of injury or death, ensure that the main power supply has been disconnected before performing any maintenance or removing any modules.
Disconnect the power supply.
To avoid potential damage to the processor, handle all modules by the ends of the carrier or edges of the plastic housing. Skin oil