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| Illustration 1 | g01344733 |
Static Switch Right Panel (1) Bypass Universal Static Switch Interface Board (2) Line Universal Static Switch Interface Board (3) General Purpose Input/Output Board | |
There are two Universal Static Switch Interface Boards in the Static Switch cabinet. The Universal Static Switch Interface Boards are mounted on the upper right panel.
The Universal Static Switch Interface Board controls the gating commands to each static switch. The Universal Static Switch Interface Board converts the logic commands into SCR gate commands. The APC2 commands enter on a separate connector and, depending on the mode of operation, the Universal Static Switch Interface Board operates the Line Static Switch. The commands are received in serial data packets. The commands are decoded by the Complex Programmable Logic Device.
The Bypass Universal Static Switch Interface Board receives commands via a connector from the Breaker and Contactor Status Board. These are discrete commands to turn off the Static Switch.
There is an onboard serial flash that stores the setup data to tell the Bypass Universal Static Switch Interface Board whether to auto turn on when power is supplied or wait. This is a setup parameter and is customer selectable.
The Bypass Universal Static Switch Interface Board has one dry contact output to indicate status. The Bypass Universal Static Switch Interface Board is used for the Maintenance Bypass option to signal if the system is in Bypass.
LED Indicators
| USI LED Indicators | ||
|---|---|---|
| LED | Board Designation | Purpose |
| 1 | D7 | Datalock with APC |
| 2 | D6 | Bypass Close Cmd |
| 3 | D5 | Auto Load On |
| 4 | D4 | Line USI |
USI Board Diagram
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| Illustration 2 | g01275430 |
Removal
- Perform the steps in the Systems Operation, Testing and Adjusting, "Internal Component Preremoval Steps (Static Switch Cabinet)" in order to de-energize the system and gain access to internal components.
- Disconnect all connectors. The connectors locations in the unit are labeled. Verify each connector label. Refer to Illustration 2.
| 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. |
- Unscrew the cross tip screw from the lower left corner of the board.
- Disconnect the seven white plastic stand-offs that connect the board to the left panel using the following method.
Note: The board must be removed from the stand-offs without bending the board.
- Pinch the head of each stand-off so that the board is not locked but is still attached to the stand-off.
- Remove the board by gently and evenly pulling the board from all stand-offs at the same time.
Installation
| 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. |
- Position the board in the cabinet over the seven white stand-offs that are connected to the left panel.
- Push the board, gently and evenly, onto all the stand-offs simultaneously. Make sure all stand-offs are locked in place.
- Insert the cross tip screw in the lower left corner of the board and screw the cross tip screw into the left panel.
- Plug the wire connectors into the correct connectors on the board. Check the labels on each connector for proper placement.
Refer to Illustration 2.