Appendix A.6. Configuring A Fieldserver To Read And Write Data To And From A Plc - FieldServer FS-8704-14 EtherNet Driver Manual

FS-8704-14 EtherNet/IP Manual Page 21 of 30

Appendix A.6. Configuring a FieldServer to read and write Data to and from a PLC.

This example makes use of the Data Table Read/Write method for passing data between the FieldServer and an
Allen Bradley PLC. The example shows configuration of a ControlLogix PLC, but all RockWell PLC's that support
Ethernet IP communications and Data Table Read/Write operations in Message blocks should be able to
communicate this way. . These map descriptors will create an explicit connection to the server and will then
transfer data in the data table format. The EIP_Tag_Name field contains the tag name referenced in the server
and the EIP_Path field represents the path (through different ports) to the server. Each port jump is separated by a
space. This field generally holds a backplane / cpu slot combination. DATA_TABLE_READ and DATA_TABLE_WRITE
are the only legal values for EIP_SERVICE.
Note that this is by far the preferred method for communicating with Allen Bradley PLC's due to it's ease of
configuration, quantity of data that can be transferred and speed of transfer.
When the FieldServer is the active component as shown below (i.e: the FieldServer Polls the PLC and not the other
way around), then very little programming is needed in the PLC, other than the Tag Creation and setting the PLC IP
Address.
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