Rockwell Automation 1747-BSN Backup Scanner Module - Manual (Page 194)

Publication 1747-UM010B-EN-P - September 2003
4 Glossary
Data Transfer Control Word (DTCW)
This word is M0:s.3410 (where s=slot number of the 1747-BSN) and is
used by the primary processor to initiate data transfers to the primary
1747-BSN. Eventually the primary processor initiates data transfers to
the secondary 1747-BSN over the HSSL, and then to the secondary
processor.
Data Transfer Handshake Word (DTHW)
This word is M0:S.3411 (where s=slot number of 1747-BSN) and is
used by the secondary processor to inform the secondary 1747-BSN
that it has received the latest data block and is ready for the next data
block.
Data Transfer Status Word (DTSW)
This word is M1:s.3410 (where s=slot number of 1747-BSN and is used
in both the primary and secondary systems to affect the transfer of
data on the HSSL.
Extended Node Capability
Functionality that allows you to use an 82 Ohm termination resistor at
both ends of the RIO link for all baud rates. This functionality also
allows for up to 32 adapters to be connected to the RIO link.
G file
The SLC file used to configure the scanner. You enter configuration
information into this file during SLC processor programming. This file
is loaded to the scanner by the SLC processor upon entering run
mode.
High-Speed Serial Link (HSSL)
2 Mbit/second link between primary and secondary 1747-BSN
modules to provide the secondary SLC processor with input, block
transfer, and user retentive data. Network status and control
information are also transferred between 1747-BSN modules on this
link.
Inhibit
A function by which the scanner stops communicating with a logical
device. The logical device considers itself inhibited if it does not
receive communications from the scanner within a certain period of
time.