Rockwell Automation 1785-BCM_BEM, D17856.5.4 PLC-5 Backup Communication Module User Manual - Manual (Page 6)

Preface
iii
Switchover is the transfer of I/O control from the primary processor to the
secondary processor.
Bumpless switchover is the transfer of I/O control from the primary
processor to the secondary processor where the operation of the process
being controlled is not affected.
Asynchronous processing is processing where the ladder program scan and
the block-transfer scan operate independently of each other within the same
scan time.
BTW is block-transfer write; transfer of up to 64 words from the processor to
the block-transfer module.
BTR is block transfer read; transfer of up to 64 words from the block transfer
module to the processor.
Smart Switch Interface is a remote I/O interface in the 1785-BCM module
that responds to secondary scanner poll commands with actual input values
from the remote I/O link, making the scanner think it is talking with
remote I/O.
For more information about components used with the 1785-BCM module in a
PLC-5 backup system, refer to the following publications:
Publication Title Publication Number
Enhanced and Ethernet PLC-5 Programmable Controllers
User Manual 1785-6.5.12
Classic 1785 PLC-5 Family Programmable Controllers Hardware
Installation Manual 1785-6.6.1
PLC-5 Programming Software Documentation Set 6200-N8.001
PLC-5 Programming Software: Installing and
Configuring the Software 6200-6.4.6
PLC-5 Programming Software: Programming 6200-6.4.7
PLC-5 Programming Software: Instruction Set Reference
PLC-5 Programming Software: I/O Configuration Software
6200-6.4.11
6200-6.4.12
Remote I/O Adapter Module (cat. no. 1771-ASB) Installation Data 1771-2.162
Related Publications