peer-to-peer communication between PLC's ControlLogix
peer-to-peer communication between PLC's ControlLogix
(OP)
Hello everybody,
I have two PLC’s ControlLogix and need to exchange some data peer-to-peer.
The data (about ten words from plc 1 to plc 2 and ten vice-versa) consist of time-critical data such as interlocks and setpoints, therefore I cannot/do not want to use Ethernet/IP explicit messages. On the other hand those data do not require ControlNet determinism. Also I do not want a ControlNet link just for this purpose cause each of the two PLC’s has already the following communication modules:
- Ethernet/IP for remote I/O purposes
- Ethernet/IP for Scada purposes
- DeviceNet for drives link
How can I exchange those data at a speed implicit-messages-like, exploiting the above networks?
Thks in advance.
I have two PLC’s ControlLogix and need to exchange some data peer-to-peer.
The data (about ten words from plc 1 to plc 2 and ten vice-versa) consist of time-critical data such as interlocks and setpoints, therefore I cannot/do not want to use Ethernet/IP explicit messages. On the other hand those data do not require ControlNet determinism. Also I do not want a ControlNet link just for this purpose cause each of the two PLC’s has already the following communication modules:
- Ethernet/IP for remote I/O purposes
- Ethernet/IP for Scada purposes
- DeviceNet for drives link
How can I exchange those data at a speed implicit-messages-like, exploiting the above networks?
Thks in advance.





RE: peer-to-peer communication between PLC's ControlLogix
As long as the Ethernet network between the PLCs is not highly loaded, implict messaging using producer/consumer tags works. I know, I have done it. A bonus you can also control the update interval for each tag.
Recommendation: place all of the tags to be transfered into a user defined structure. As long as this structure is less than about 900 bytes long, this will be the most efficient way to transfer data.
RE: peer-to-peer communication between PLC's ControlLogix
The nice thing about this option is it gives you the ability to do it all over Ethernet and control the timing.
See http://www.toolboxopc.com