Rockwell Automation 1747-BSN Backup Scanner Module - Manual (Page 12)

12 Backup Scanner Module
Publication 1747-5.38
Switchover Conditions
The 1747-BSN module transfers control from the primary to the secondary
processor (switchover) if one of the following fault conditions occurs in the
primary system:
• power failure
• major fault in the processor
• 1747-BSN module fault
• primary processor mode change from Run to Program
Installation
Determining Power Requirements
The BSN module is powered through the backplane of the I/O chassis. Before
installation, make sure that your modular SLC power supply has adequate reserve
capacity. The BSN module requires 800 mA at 5V.
Note: In order for switchover to occur, both primary and
secondary modules must be working without faults prior
to the event that triggers the switchover.
!
ATTENTION: Disconnect system power before attempting to install, remove, or
wire the module.
Important: Use separate power sources for the primary and secondary
processors to protect against interruptions and incoming power
failures.