COVER 2266051 - Caterpillar

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 BoardThere 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
Table 1
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
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.
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