The 1747-BSN module provides backup functionality for the following:

• DH+ or RIO on a single pair of modules – Both may be backed up when two

or more pairs of modules are used.

• RS232 – Any RS232 device communicating with channel 0 of the SLC

controller may be backed up provided hardware-handshake lines are not

required. These ports only allow switchover of the transmit, receive and

ground wires for RS232.

Configuration Errors

The module reports the following configuration errors by flashing the fault LED:

• two 1747-BSN modules are configured with the same address

• LSL addresses are not consecutive (addresses must be numbered 0, 1, 2,etc.)

• last LSL switch is not set in the last module in the link

• last LSL switch is set in a module that is not the last in the link, or

• primary and secondary modules do not have the same configuration settings

(secondary module shows the configuration error)