CUP AS 2M0881 - Caterpillar

Illustration 1 g00795767
The system of the programmable logic controller (PLC) is shown with the processor and the base assembled. The programmable logic controller (PLC) consists of the following components:
Controller
Base
Input module
Output moduleThe processor has a memory module and a battery backed up RAM. The memory module stores the program for the annunciator. The processor attaches to the inside of the base. The base is powered by 24 DCV. The base is equipped with 16 inputs. The base is also equipped with 12 outputs (6 relay and 6 FET). The status of the inputs and outputs are displayed on the front of the base. The status is represented by LED indicators.The system is equipped with an input module which adds 16 additional inputs in order to increase the capacity of the PLC. An input is active whenever 24 VDC is applied to that input. The status of each input is displayed on an LED indicator on the module. The system is equipped with an output module which adds 16 additional outputs in order to increase the capacity of the PLC. The outputs are sourcing drive outputs that use 24 DCV. An output is active whenever 24 DCV is being supplied to the load that is attached to that output. The status of each output is displayed on an LED indicator on the module.Refer to the Tables 1 and 2 for descriptions on the LED indicators.
Table 1
LED    Color    Indication    
"POWER"     off     no input power    
    green     The power is on.    
"RUN"     off     The controller is not running in the "Run" mode or the "REM" mode.    
    green     The controller is running in the "Run" mode or the "REM" mode.    
    green flashing     The controller is running in the "Run" mode.
The memory module is transferring data.    
"FAULT"     off     no faults    
    red flashing     The program has a fault.    
    red     hardware fault    
"FORCE"     off     no forces    
    amber     forces are installed.    
"BATTERY LOW"     off     The battery is okay.    
    red     The battery needs to be replaced.    
"COMM 0"     off     no communication    
    green     communications are active.    
"COMM 1"     off     no communication    
    green     communications are active.    
"DCOMM"     off     user-defined communications are active.    
    green     default communications are active.    
INPUTS     off     input is not energized.    
    amber     input is energized.    
OUTPUTS     off     output is not energized.    
    amber     output is energized.    
Table 2
LED    Error    Probable cause    Recommended Action    
All LED indicators are off.     No input power     No line voltage is present.     Verify the line voltage and the connections to the controller.    
        Power supply is overloaded.     This problem can occur intermittently when the outputs are