RSLogix5000 sharing bits

How can I use an XIC or XIO bit from one Logix5000 plc that is on an ethernet network in a rung of logic in another PLC on that network?

The scheduled data exchange between ControlLogix controllers is called "Produced/Consumed Tags". It can be done over a backplane or over ControlNet or EtherNet/IP networks.

You can't exchange actual BOOL datatype tags; I generally exchange DINT tags or arrays of them, then address individual bits in your logic.

Produced/Consumed Tags are well described in several places; in the Online Help, in the RA Knowledgebase, and in documents like publication ENET-UM001, EtherNet/IP Modules in Logix 5000 Control Systems (Chapter 7).

Welcome to the forum.

XIO and XIC are computer instructions, not bits. Are you wishing to read a physical IO point or a memory tag?

Thank you for the correction. I am looking to read Physical IO, a level switch in another side of the plant. If the tank is empty I don't want a mixer to run.

Ken

Thank you, the Produced/Consumed tags is the piece I was missing. Rockwell doc pm/1756-pm011_-en-p.pdf explains it quite well. I Never did this before looking forward to trying it out.

For physical I/O modules in ControlLogix, there's also the option of using a Listen Only I/O connection. The same ControlLogix and EtherNet/IP user manuals should illustrate that too.

Ken has mentioned "Liston-Only" connections.

There is also the option of "Sharing" the input module, so that both controllers have ownership of it. For this to be successful, then the configurations in both projects must be identical. (I use Copy/Paste to make this easy).

Sharing, IMHO, is preferable to Listen Only, since either controller can be taken down without affecting the other.

In a Listen-Only setup, if the "Owner-Controller" is removed from its chassis, the input module no longer has a connection, and stops transmitting its data.

It works like this -

1. One controller will power-up first, and will send its connection request to the input module, by attempting to download the Configuration tag.
2. The input module accepts the configuration tag (on the basis that it has no stored configuration - the modules are not retentive).
3. Then the second controller (and we have no way of determining which will be first, or second), will attempt the connection by downloading its configuration tag.
4. The input module checks the incoming configuration is consistent with the configuration it already has from the first controller, and if it is, accepts the second connection as well.


An input module can have many owner-controllers in a full sharing scenario, the connection will only be made if the configurations match.

So long as a shared input module has at least one connection with a controller, it will still multicast its data.

I keep saying Input Module, not I/O module, because Output modules cannot have multiple owners, for obvious reasons.

Thank you all for the inputs, Pun not intended . I had no idea you could use the same input card for two controlers,interesting. I ended up using some messaging instruction.