DH+ Link ID -- how to determine?

I've got an existing DH+ network. How do I determine what LinkID it is using?

I've got a 1756-DHRIO card. It needs its own unique LinkID for the module and then I have to match the network, right?

Thx!

In RSLinx go to the DH+ RIO card and right click to get to propertiesits in there
If this is a new install then I set mine to the same as the node address that it uses

I'll try that on an existing machine. Thx.

Link ID's are different from DH+ Node Addresses.

Think of a DH+ network like a residential street. Every house has an address, just like every node on the DH+ has an address. I live here in my PLC5 at #3 Oak Street.

There's another DH+ nearby; it's called Elm Street. There's a #3 Elm Street too.

So if I want to send a message to #3 Elm Street from #3 Oak Street, I need to send it through a gateway on my own street, and know which street it's headed to. The Street name is the Link ID.

Now here's the surprise: Link IDs are ignored for local messaging. If I send a message locally from #3 Oak Street to #5 and don't specify which street it's on, it just goes to #5 Oak Street.

90% of DH+ installations have just the one network so the Link IDs end up being left at their defaults, and nobody notices because they never need to send a message beyond Oak Street.

Where you can get really interesting is when you use a ControlLogix and 1756-DHRIO modules to create Link ID's that have a backplane and ControlNet or Ethernet paths between the two DH+ networks. You could separate Oak Street from Elm Street by a wide area Ethernet LAN and they'd never know it.

Where you can get really interesting is when you use a ControlLogix and 1756-DHRIO modules to create Link ID's that have a backplane and ControlNet or Ethernet paths between the two DH+ networks. You could separate Oak Street from Elm Street by a wide area Ethernet LAN and they'd never know it.[/quote]


So, you're saying I could brige two Elm streets with Ethernet and the local PLCs wouldn't know it?