Installing The Terminator; Compatibility Of 1771 Remote I/O Products With Extended Node Numbers - Allen-Bradley D Series User Manual

Chapter 2
Installing Your Module

Installing the Terminator

Compatibility of 1771
Remote I/O Products with
Extended Node Numbers
2-14
If this is the last remote I/O adapter on the link, you must use a terminating
resistor to terminate both ends of the remote I/O link (scanner end and last
adapter end). The size of the terminator is determined by the system
configuration.
Older configurations use a 150 ohm resistor at both ends. With newer
products that can support it, you can use an 82 ohm terminator at both
ends. The 82 ohm terminators provide "extended node" capability which
allows you to have up to 32 physical devices on the RIO link. (The number
of logical racks capable of being addressed by the scanner is not affected.)
This allows 1/4, 1/2 and 3/4 racks, Dataliners, Redipanels and Panelview
devices to be attached to the link.
ATTENTION: Devices that are operating at 230.4K Baud must
have 82 ohm terminators in place for proper operation.
Certain products are not compatible with the extended node capabilities
obtained with the use of the 82 ohm terminator resistors. These products
are listed below.
Table 2.G
Non compatible Products
Device
Scanners 1771 SN
1771 SD
1772 SD2
1775 SR
1775 S4A
1775 S4B
Adapters 1771 AS
1771 ASB
1771 DCM
Miscellaneous 1771 AF
1771 AF1
Series
All
All
All
All
All
All
All
Series A
All
All
All