Contents 
vi  PACSystems* RX7i & RX3i TCP/IP Ethernet Communications User Manual  GFK-2224Q 
6.8  Write EGD Exchange (4003) .................................................................................................................... 104 
  Write EGD Exchange Command Block ..........................................................................................................104 
6.9  Masked Write to EGD Exchange (4004) ................................................................................................ 106 
  Masked Write EGD Exchange Command Block ........................................................................................106 
Chapter 7  Programming SRTP Channel Commands ............................................................................. 110 
7.1  SRTP Channel Commands ...................................................................................................................... 110 
  Channel Operations .................................................................................................................................................111 
  Aborting and Re-tasking a Channel ................................................................................................................111 
  Monitoring the Channel Status ..........................................................................................................................111 
  SRTP Channel Commands in a Redundant System ................................................................................111 
  Executing a Channel Command .......................................................................................................................112 
7.2  COMMREQ Format for Programming Channel Commands ............................................................. 113 
  The COMMREQ Command Block: General Description .........................................................................114 
  Establish Read Channel (2003) ..........................................................................................................................116 
  Establish Write Channel (2004) ..........................................................................................................................120 
  Send Information Report (2010) ........................................................................................................................123 
  Abort Channel (2001) ..............................................................................................................................................125 
  Retrieve Detailed Channel Status (2002) ......................................................................................................126 
7.3  Programming for Channel Commands ................................................................................................ 127 
  COMMREQ Sample Logic ......................................................................................................................................128 
  Sequencing Communications Requests .......................................................................................................130 
  Managing Channels and TCP Connections .................................................................................................130 
  Use “Channel Re-Tasking” To Avoid Using Up TCP Connections .....................................................131 
  Client Channels TCP Resource Management ............................................................................................131 
  SRTP Application Timeouts ..................................................................................................................................132 
7.4  Monitoring Channel Status .................................................................................................................... 132 
  Format of the COMMREQ Status Word .........................................................................................................132 
Chapter 8  Modbus/TCP Server .................................................................................................................. 135 
8.1  Modbus/TCP Server ................................................................................................................................. 135 
  Modbus/TCP Server Connections .....................................................................................................................135 
  Modbus Conformance Classes ..........................................................................................................................135 
  Server Protocol Services........................................................................................................................................135 
  Station Manager Support .....................................................................................................................................135 
8.2  Reference Mapping .................................................................................................................................. 135 
  Modbus Reference Tables ....................................................................................................................................136 
  Address Configuration ...........................................................................................................................................137