Allen-Bradley 1747-SN Installation Instructions Manual page 4

4 Remote I/O Scanner
Overview
The Remote I/O (RIO) Scanner, 1747-SN, enables communication between an
SLC™ processor and remotely located 1746 I/O chassis and other RIO-
compatible Allen-Bradley operator interface and control devices. The 1747-SN
scanner communicates with remote devices using the A-B Remote I/O link. The
RIO link consists of a single master (scanner) and multiple slaves (adapters).
Communication between devices occurs over twisted-pair cable with the devices
daisy-chained together. Maximum distance for remote communication is
3,048 m (10,000 ft.). The scanner is compatible with any standard RIO adapter
device.
The SLC processor transfers a maximum of 4 logical racks (32 input and 32
output image words) of discrete remote I/O data into the SLC input and output
image files. You can adjust the size of the scanner image files during
configuration of your SLC system so that the scanner only transfers the discrete
I/O data required by your application program. The 1747-SN Series B or later
RIO Scanner can be configured to transfer up to 64 words of data to a remote
device via block transfer. Refer to publication 1747-6.6, Remote I/O Scanner
User Manual, for information on configuration, programming, and block
transfers.
The SLC 500™ processor (SLC 5/02™ or higher) supports multiple scanners in
its local I/O chassis. The maximum number is dependent on the following:
• backplane power requirements (power supply dependent)
• SLC 500 processor I/O data table limit (4,096 input and output bits)
• processor memory to support the application (SLC processor dependent)
SLC 5/02 or
later processor
Dataliner ™ Message Display
Publication 1747-5.33
RIO Scanner
(Master of the RIO Link)
Local SLC Chassis
(Adapter/Slave)
1747-ASB Module
(Adapter/Slave)
Remote Chassis
PanelView ™ Operator Terminal
(Adapter/Slave)
Remote
Expansion Chassis
RediPANEL ™
(Adapter/Slave)