Introduction 
Revision 6    HC900 Process & Safety Controller User and Installation Manual  13 
21 April 2017 
Feature Summary 
Hardware 
  Modular rack structure; components are ordered individually as needed 
  CPU with Ethernet and isolated RS485 communications 
  Easy to assemble, modify, and expand 
  C30 and C30S controllers provide local I/O connections while C50/C70 and C50S/C70S Controllers provide for 
remote input/output rack connections over a private Ethernet-linked network 
  Parallel processing - a microprocessor in each I/O module performs signal processing, to preserve update rates 
  Power supplies - provide power to CPU rack and Scanner I/O racks 
Redundancy 
  Redundant C75 CPU 
  Redundancy Switch Module (RSM) – required between redundant CPUs 
  Redundant Power Supply – provides redundant power to any CPU rack or Scanner2 I/O rack 
  Power Status Module (PSM) – required when using a second power supply in Scanner2 I/O rack 
Communications 
All CPUs (except where noted): 
  Serial Ports: 
  Legacy 
 Two serial ports, configurable for RS-232 or galvanically isolated RS-485 communications.   
 RS232 port can be used for link to PC for 900 Designer configuration tool (up to 50ft/12.7 Meters) 
or via modem.  Also can be configured for Modbus RTU, master or slave. 
 RS 485 port used for 2 wire link to legacy operator interface (ELN protocol) or can be configured 
for Modbus RTU, master or slave communications (up to 2000 Ft /600 Meters).  
   New Controllers 
  Two isolated RS 485 communications ports 
 USB to RS485 cable must be obtained to support link to PC for 900 Designer configuration tool      
 Can be configured for Modbus RTU, master or slave communications (up to 2000 Ft /600 Meters)