Allen Bradley PLC as Ethernet/IP Adapter


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I have communicated well with Allen Bradley PLC as Ethernet IP master/scanner. but not sure if an Allen Bradley PLC 1769-L33ER be configured as Ethernet/IP slave or adapter? please confirm.

James Ingraham

No, a 1769-L33ER can not be configured as an EtherNet/IP slave or adapter. However, using produced and consumed tags can effectively make it an adapter. Note that this only works with another Allen-Bradley Logix processor.

-James Ingraham
Sage Automation, Inc.
Hello Madhumati,

If I understand you correctly, your intention is to set up compactlogix PLC so they will behave like PLC-5 CPU which the Ethernet port able to be configured as remote IO (RIO) adapter. Actually, compactlogix is slightly different with PLC-5, they don't provide PLC-5 RIO protocol. so compactlogix can't be configured as a PLC-5 RIO. Compactlogix native Ethernet port only available for three communication methods:

- Ethernet/IP: Ethernet/IP or CIP is a peer to peer type protocol. means each node will be able to initiate communication to other node they would like to be connected. so concept of master slave is not applicable here. CIP is used if conpactlogix need to communicate with other compactlogix, controllogix, Aadvance, Trusted or other AB PLC/drive family except for PLC-5 and SLC-500 or 3rd party devices with CIP supported. For this protocol, produced-consume method or CIP MSG instruction will be used.

- Ethernet with PLC-5 mapping: with this way PLC-5 will be able to initiate communication with Compactlogix/controllogix like they are communicating with other PLC-5 using MSG instruction. on the compactlogix side, using RSlogix5000 you will need to map RSLogix5000 tags, which is text based, into PLC-5 variables (N, F, B, etc).
- Modbus TCP: With this methods you will be able to configure your compactlogix as a slave or master, depend on your requirements. but since Modbus is not firmware level supported by Logix familiy, you will need to create Modbus protocol program within the logic program using ladder or function block. You can download Modbus program sample from AB website for quick start.