UPS 1000S/ UPS 1200S Uninterruptible Power Supplys Caterpillar

Illustration 1	g01279664
Display Interface Board Location (1) Display Interface Board (2) Graphics Master Board

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(1) Display Interface Board (2) Graphics Master Board

The function of the Display Interface Board is to provide an interface between the front panel display and the APC2 Board.

Power to the Graphics Master

The Display Interface Board has an isolated 12 VDC supply and an isolated 5 VDC supply in order to power the Graphics Master Board. Input power is from the unregulated 24 VDC supply on "J1". The output of the 5 VDC and 12 VDC isolated supplies are on "J3".

RS-232 Channel A

Graphics Master serial channel A connects to the Customer Tray. A laptop computer can be connected for service purposes. Graphics Master serial channel A is configured for 3.3 VDC and drives an RS-232 interface.

The Customer Tray is accessed from the top of the UPS.

RS-232 Channel B

The Graphics Master serial channel B is connected to the Customer Tray. The Graphics Master serial channel B is used to connect the optional modem. The optional modem is located in the Customer Tray on single MMU systems. The Graphics Master serial channel B is configured for 3.3 VDC and drives an opto-coupled RS-232 interface.

RS-485 for Modbus

The RS-485 channel can be configured on the external terminal strip in the Customer Tray for either 4 wire (full duplex) or 2 wire (half duplex) operation. Refer to Systems Operation, Testing and Adjusting, RENR7654, "Flywheel Field Coil Current - Calibrate" for more information on Modbus setup.

Fuses

The types and functions of the fuses are indicated in Table 1. Visually inspect the fuses and replace if the fuse is blown.

Display Interface Board Diagram (Version 1)

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Display Interface Board, Version 1

Display Interface Board Diagram (Version 2)

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Display Interface Board, Version 2

Removal

1. 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.

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NOTICE
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 potential. Wear an approved wrist-strap grounding device. Do not touch the bus connector or connector pins. Do not touch circuit components inside the module. If available, use a static-safe work station.

2. Disconnect all connectors from the board. The connectors locations in the unit are labeled. Verify each connector to make sure that the label is present and legible.

   Refer to Illustration 3.

3. Unscrew the cross head screw from the lower right side of the board.

4. Disconnect the eight white plastic standoffs connecting the board to the left panel using the following method.

   Note: The board must be removed from the stand-offs without bending the board.

   1. Pinch the head of each stand-off so that the board is not locked to the stand-off but is still attached to the stand-off.

   2. Remove the board by gently and evenly pulling the board from all stand-offs at the same time.

Installation

1. Position the board in the cabinet over the eight white stand-offs that are connected to the left panel.

2. Push the board, gently and evenly, onto all the stand-offs simultaneously. Make sure all stand-offs are locked in place.

3. Insert the cross head screw in the lower right side of the board and screw the cross head screw into the door panel.

4. Plug the wire connectors into the correct connectors on the board. Check the labels on each connector for proper placement.

   Refer to Illustration 3.