PLC5 to PLC5 Message over Data Highway

[billy.nfp]

Hey everyone!

I am trying to set up some messaging between two of our older PLC's, having difficulty getting the configuration nailed.

I've made an integer table in both PLC's, and I have a MSG table in one right now. Eventually I plan to set up read/write both ways, but that should be relatively trivial once I get one direction working.

The message path is as follows:

PLC5/40E series D Rev B
Ethernet on Channel 2 (192.168.1.76)
DH Bridge (192.168.1.50)
Ride the Data Highway to a PLC5/30C Rev H, which is node 77o

In trying to set this up I've tried multiple configurations on the PLC5/40E. I tried to do a multihop configuration, as that seemed pretty intuitive to set up, but was greeted with "Ethernet Multihop is not available for this processor type".

So I am currently assuming that it'll have to be some kind of IP path, as I've done before with CLX->PLC5 messaging. Under the target device section, I've got my data table set correctly, multihop set to no, and Ethernet IP Address is where I'm stuck. I've tried several variations, such as 192.168.1.50, 1, 2 - that should be the DH Bridge, backplane, slot 2, which is the DHRIO card that has the data highway network on it. I've tried following the routing table in my RSLINX, which would give something like 192.168.1.50, 20, 2, 8, (then maybe 77?). That would be the DH Bridge, Link 20 is the backplane, slot 2 is the DHRIO card, link 8 is channel B, which is the data highway channel. I've tried including the 77 (octal node of the PLC5/30C), I've tried 63 (decimal conversion), and I've tried excluding that entirely.

Any advice would be greatly appreciated. This data highway network was put in before my time, and has zero documentation, network drawings, etc.

Thanks!

 

[Ken Roach]

Welcome to the PLCTalk forum community !

I think your problem might be the PLC-5/40E firmware support for EtherNet/IP.

I checked with the Knowledgebase, and it says the PLC-5E controllers support EtherNet/IP after:

Series F - All
Series E, revision D.1
Series D, revision E.1
Series C, revision N.1

Because you have Series D, Rev B firmware, that explains why RSLogix 5 gives you an "Ethernet Multihop not available for this processor type".

Even though the target is another PLC-5 on DH+, because the message has to get through a 1756-ENxT module it needs to be CIP Ethernet/IP.

I don't think that DH+ Remote Link addressing will do what you need in this case because the message can't get through the 1756-ENxT to the backplane then to the 1756-DHRIO.

If you had another DHRIO to connect to one of the PLC-5/40E's DH+ ports, it would be able to bridge an intermediate TCP/IP network because you can set up the routing tables for that purpose, and to the PLC-5 it looks like "DH+ Remote Link Addressing", like the ancient 1771-KA.

 

[Ken Roach]

I admit I don't remember the details of how the RSLogix 5 message configuration looks when it's going to go out to a 1756-ENxT and 1756-DHRIO, then on to the DH+.

I believe that you have to set up a routing table in the 1756-DHRIO (which is tricky as heck).

It's much easier to send a message from a ControlLogix to a PLC-5 on Ethernet; you address the message to the DHRIO, and give it sufficient information (which channel, which target node) to execute the message on DH+ and process the reply.