CLX Produced/Consumed Tags

I am currently working on a project that uses 4 Controllers and a RIO. The project standard requires we use Produced and consumed tags for communication between processors. My question is, Can I use prod/cons tags in both directions? 1 Rack will need to know when certain tags go Hi and react then send commands back to the 3 remaining racks.

Would there be a conflict with the parent/child relationship if a controller is both?

I hope this is clear enough of a question.

Yes you can have both consumed and produced tags on the same controller. It isn't a master/slave setup like modbus or such. It's done on a tag by tag basis. When a tag is produced, it is basically broadcast, and you configure the consumer to listen for it. So any one controller can be broadcasting and listening.

Awesome thanks for the reply. That makes things a lot easier.

I'm a little confused by "uses 4 Controllers and a RIO".

Based on other comments, I'm assuming you have 4 controllers in 4 separate racks. What is the network connecting these racks? ControlNet or Ethernet/IP?

Either way it is important that you plan your produce/consume tags in a way that allows you to make changes without shutting down all the processors. I like to use arrays of DINTs in each proccessor, one for produce and one for consume from each other processor. The tags in my program alias these arrays.

This allows me to schedule the ControlNet once and still be able to add produce/consume tags to my programs. Otherwise you have to re-schedule each time you add a tag which means all processors in program mode.

I really don't like seeing project standards that say "we use Produced and consumed tags for communication between processors". There are good reasons to use messages over produce/consume. Such a requirement just limits your ability to design a good system.

The communication is going to be through ethernet. This will be for an automated fueling system for a Nickel Mine with 1 Rack on surface with the RIO controlling pumps and valves and the other 3 Racks will be on 3 different levels of the mine controling pumps and valves also and Level transmitters. Its all Copper to Fiber cabling to get to surface.

The Surface PLC will be consuming a Tag(DINT) from each of the mines levels and each Level will only receive or consume 1 word from surface.

I guess I should have divulged a little more info on the project to help clear things up.

In the past I have used MSG instructions with RSLogix 5 but this new project is RS5000 using only Function Block and its an entirely new animal.

Thanks for the responses.

mellis said:

I really don't like seeing project standards that say "we use Produced and consumed tags for communication between processors". There are good reasons to use messages over produce/consume. Such a requirement just limits your ability to design a good system.

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I completely agree with this.

You need the flexibility to pick the right method for the right application. On the machine I am currently working on we used messages to transfer data that needs to be 'on-demand' like grabbing part data when transferring from module to module. We used produced/consumed to send things that need to be constantly monitored, like machine status or handshake signals.