UPS 750 Uninterruptible Power Supply Caterpillar

Illustration 1	g06058146
Inter-System Network board (ISN)

The Inter-System Network (ISN) board is used to create a control network between paralleled series UPS750. The board is also used to create a control network between a series UPS750 and the DC expansion cabinets. A control network is composed of three high-speed RS-485 half-duplex transceivers. For redundancy of the controls network, a second ISN board is required.

When used to create a controls network between paralleled UPS, the network is called UPSNet. UPSNet is a star network that requires the inclusion of an Inter-System Hub (ISH) board. The ISH is powered by the ISN via an isolated 48 VDC supply distributed to the ISH by a CAT5 interconnect.

When used to create a controls network between a UPS and the DC expansion cabinets, the network is called CSNet. CSNet is a daisy-chained network and does not require the ISH board.

Inter-Network System (ISN) Board Removal

Note: Always practice Electrostatic Discharge (ESD) prevention when handling printed wire assemblies (PWAs).

1. Ensure that all pre-removal steps are performed for the Extended Runtime Cabinet (EXRC) before gaining access to internal components.

   Note: The system must be shut down before removal steps can be performed.

2. Disconnect all board connectors. The connectors are labeled as to their locations in the unit. Verify each connector label.

3. Disconnect the white plastic stand-offs connecting the board to the left panel using the following method:

   Note: Do not bend the board when removing from the stand-offs.

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

   2. Gently and evenly pull the board from all stand-offs at the same time to remove the board.

Inter-System Network Board (ISN) Installation

Note: Always practice Electrostatic Discharge (ESD) prevention when handling printed wire assemblies (PWAs).

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

2. Gently and evenly push the board onto all the stand-offs simultaneously. Ensure that all stand-offs are locked in place.

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