30    HC900 Process & Safety Controller User and Installation Manual  Revision 6 
    21 April 2017 
Redundancy Switch Module (C75/C75S only)  
The Redundancy Switch Module (RSM) is shown in Figure 13.  
It sits between C75/C75S controllers in the redundant controller rack. Left Controller is 
designated 
 “CPU-A”; right Controller is “CPU-B.” Features include: 
1.  Lead/Reserve controller status indicators.  
2.  Keyed switch for manual changes to controller modes or to facilitate a Manual Fail 
Over.  
 
 
 
 
 
 
 
Figure 13 – Redundancy Switch Module 
 
Scanner 1 Module (S50/S50S only)  
 
900S50, Scanner1 module is shown in Figure 14. 
It sits in the I/O rack and provides the link between the controller and 
remote I/O. Features at the front of the module include: 
1.  LED status/diagnostics indicator for scanner functions.   
2.  One private Ethernet 10/100 Base-T Port; connects to the I/O 
expansion port on Controller Module (or to a port on a Switch that 
connects to the Controller Module) 
3.  LED status/diagnostic indicators for communications functions. 
 
  Figure 14 – Scanner 1 Module