GE GFK0579B User Manual

Series 90–70 Remote I/O Scanner User’s Manual – July 1992

Redundant Bus Configuations

Many different redundant bus configurations are possible. Three basic ways of using a
Remote I/O Scanner with a redundant bus are described below.

H A Remote I/O Scanner can be installed directly on both cables of the dual bus

pair.

The Remote I/O Scanner is configured to operate as a bus switching device in

addition to performing its normal remote drop functions.

Here, two single–rack remote drops are installed on a dual bus. The Remote I/O
Scanner in each remote drop would be set up as a bus switching device.

a44974

BUS A

BUS B

N
E
R

RACK 0

N
E
R

RACK 0

A bus stub may be connected to a Remote I/O Scanner that is configured as a bus
switching device, allowing up to seven additional devices to utilize its bus
switching action. Devices on a bus stub are independent Genius devices. When
bus switching is controlled by a Remote I/O Scanner, as shown below, the devices
on the bus stub are not part of the remote drop. Their data does not count toward
the remote drop’s data total.

ÏÏÏÏÏÏÏÏ

ÏÏ

BUS A

BUS B

ÏÏÏÏ

ÎÎÎ

BUS

STUB

P
S

S
C

N
N
E
R

P
S

S
C

N
N
E
R

a44878

RACK 0

ÏÏÏÏ

UP TO 7 ADDITIONAL DEVICES