Help me read a word?

Hi.

I need assistance setting up a MSG read instruction in a PLC 5 to read from a ControlLogix.
Its quite a complex set-up so im a bit stuck.

The PLC 5 is a 5/60(iirc) called PO04 and i need to read from a Control Logix L55 called KDSC.

PO04 is connected via (fiberoptic) DH+ to a PLC5/250 PI. PO04 is node 16, PI is node 6(iirc). The PI has an Ethernet module allowing it to talk with our site (and large area) wide SCADA system. The Ethernet from the PI, servers and workstations are all connected to a managed switch.

KDSC is connected via (fiberoptic) Ethernet to the managed switch so it can talk with the SCADA system. Its IP address is 172.xx.xx.51

Any ideas? Im stuck. I only need to read 1 word :/ (or write it into PO04 from KDSC)



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I don't think you're going to be able to do this in one step using your current configuration. I don't think you can use PI as a gateway to move information directly from KDSC to PO04. You'll probably have to set up a message command to send the information from KDSC to PI over ethernet and buffer it there. Then set up a separate command to get the word from PI to PO04 over DH+. Depending on your tolerance for lag, this may be OK. I would definitely set up watchdogs on both links, and include a "good data" bit with the information being sent over DH+ in the event the ethernet connection fails while the DH+ connection continues.

I don't know off the top of my head, but there may be a way to get a PLC 5/250 (PO04) on ethernet which would then let you make the jump in one step. I'm sure someone will be along shortly if this possible.