SWITCH GP-START 3E0156 - Caterpillar

The General Purpose Interface Board in the Controls Cabinet is located in the middle of the left panel.
Illustration 1 g01277292
Controls Cabinet Left Panel (17) Breaker and Contactor Status Board (18) Remote EPO Terminal Block (19) T8 Modem Power Transformer (20) T6 Transformer (21) General Purpose Interface Board (22) Fan Power Fuse Block (23) Fuses F29-F32 (24) Fuses F20-F22 (25) Fuses F25-F28 (26) EPO Reset (27) Neutral Distribution Terminal (28) K1 Motor Power Relay (K9)Multidrop Bus
The General Purpose Interface Board provides serial data over the UPS 1200 Multidrop Bus. The General Purpose Interface Board functions as a slave on this bus, receiving commands from the APC-2 and responding with status information.The General Purpose Interface Board has a jumper-selectable 100-Ohm terminating resistor for the Multidrop bus. Jumper "JMP9" provides terminal resistance. There is also a switch that sets the Node ID. Set the General Purpose Interface Board Node ID and terminating resistor jumper to the settings on the following table.
Table 1
Controls GPI Settings    
Node ID    1    
Terminating Resistor     JMP9 - Never installed    Refer to Systems Operation, Testing and Adjusting, RENR7654, "Multidrop Network - Setup" for information on setting up the Multidrop Network.Fan Tachometers
The General Purpose Interface Board provides circuitry to read magnetic tachometer signals for the three fans in the Controls Cabinet. Sensors in each fan provide once-per-revolution digital pulses to the General Purpose Interface Board. These pulses are digitized by the General Purpose Interface Board and relayed to the APC-2 in the Controls Cabinet.Temperature Measurement
The General Purpose Interface Board provides the system with temperature measurements from an on-board thermistor (R37) that measures the temperature near the General Purpose Interface Board and a remotely located thermistor that measures the DC power supply temperature. The General Purpose Interface Board digitizes temperature information and makes the data available to the APC-2.There is also a thermistor connected to connector "J11" that measures the temperature of the Filter Inductor.General Purpose Inputs
The General Purpose Interface Board monitors the status of the following components:
Two DC Power Supply Boards
Two sets of AC Filter FusesStatus signals for the components are received via the General Purpose inputs on the General Purpose Interface Board. The status signals are then digitized and sent to the APC-2 board in the Controls Cabinet.LED Indicators
Table 2
Controls General Purpose Interface Board LED Indicators    
LED    Board Designation    Purpose    
0     D0     Filter Fuse 1    
1     D1     Filter Fuse 2    
2     D2     Power Supply 1    
3     D3     Power Supply 2    
    D14     Datalock with APC    Controls General Purpose Interface Board Diagram
Illustration 2 g01277775
Removal
Perform steps in the Systems Operation, Testing and Adjusting, "Internal Component Preremoval Steps (Controls Cabinet)" in order to de-energize the system and gain access to internal components.
Electrostatic discharge can damage integrated circuits or semiconductors if you touch bus connector pins. When not in use, keep the module in the static-shield bag. Follow these guidelines when you handle any module:Touch a grounded object to discharge static