GE RX3i User Manual page 181

Chapter 9. Modbus/TCP Client
15
16
Rung # 15: The COMMREQ Function Block has three input parameters and one output parameter.
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The IN field points to the starting location of the Command Block parameters (%R00301 in this example).
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The SYSID field of the COMMREQ Function Block defines the target rack and slot of the Ethernet interface to
receive the command data. This hexadecimal word value gives the rack (high byte) and slot (low byte)
location of the Ethernet interface module.
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The TASK field of the COMMREQ Function Block indicates which mailbox task ID to use for the specified rack
and slot. For the RX3i and Rx7i ETM001 Ethernet interfaces TASK must always be set to zero. For
PACSystems CPU embedded Ethernet interface, TASK must be set to 65536 (0x10000) to address the CPU's
Ethernet daughterboard.
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The FT output (energizes the CLOSE_FLT coil in this example) is turned ON (set to 1) if there were problems
preventing the delivery of the Command Block to the Ethernet interface. In this case, the other status
indicators are not updated for this COMMREQ.
Rung # 16: When ETH_READY is set the CRS word for the Close Modbus/TCP Connection COMMREQ is
monitored for a status of 1, indicating that the Close COMMREQ completed successfully. The CRS word change
to 1 sets coil CLOSE_SUCCESS.
168 PACSystems* RX7i & RX3i TCP/IP Ethernet Communications User Manual
Figure 64: COMMREQ Ladder Logic Segment (continued)
GFK-2224Q