Possible to do READ MSG to PLC5 from Contrologix via Ethernet?

[harryting]

Is it possible to MSG to PLC5 from Contrologix via Ethernet?

I know it's possible to do write/read at the Contrologix processor to the PLC5 series but I also remember from somewhere that it is better to do READ.

 

[Oakley]

Yes it is possible. I do it all time.


Be sure to have an array in the ControlLogix for the data, then have a PLC/SLC routing table set up - this can only be done offline. Then in the PLC5, just do a MSG Read.

I too recall that Reads were better than Writes. One personal reason, I don't like for data to "appear" in my data tables without being able to control them.

 

[Ken Roach]

Remember that PLC-5E controllers haven't always had the CIP Ethernet protocol that ControlLogix uses. Your PLC-5E (or 1785-ENET sidecar) firmware has to meet a minimum revision to be able to do "Multi-Hop" messaging, which allows it to communicate with ControlLogix.

RA Knowledgebase Answer ID# 16780 has the minimum revisions of PLC-5E Series C, D, and E controllers that support CIP. Series F controllers have had CIP since launch.

PLC-5E Series C Rev. N.1
PLC-5E Series D Rev. E.1
PLC-5E Series E Rev. D.1

 

[Oakley]

See Answer 41947 on Rockwell's tech support website for more information.

 

[harryting]

Thanks, guys.

It turns out the PLC5 is on DH+, I just thought it was on Ethernet because I have been talking to it via a RSLinx Gateway PC for many years (yet another senior moment). The PLC5 is Series E though.

The contrologic (L63) does have a DH+ card so I should be all set.