two controllogix on controlnet

Hi all,

I want to install two controllogix(L62 and L61) over controlnet network, each controller has its own I/O. how do I build up communication between two *******ler? Does I need two program for each Controller, or can I use one program and download to two seperate Controller?

Thanks a lot!

There are two methods of transferring data between the controllers, Producer/Consumer, and Messaging.

Which you choose will depend on how fast and repeatable (in time) you want that data to be transferred. You may have multiple pieces of data, some that is required rapidly and at a fixed rate, and some that is only required when certain conditions are met.

If you choose the Produce/Consume model, then there is no coding needed in the PLC to make the data transfer happen. You configure a tag in the "sender" as a Produced Tag, specifying for how many Consumers, and then configure an identical tag in the "receiver" as a Consumed tag. This tag you also specify the comms path to the Producer controller, and the update time. Once the two tags are configured correctly, the data transfer occurs automatically when the programs are downloaded to the controllers. This data transfer is deterministic, meaning if you ask for data update at, say, 20mS intervals, then it will occur at 20mS intervals. This works even if the controllers are in Program mode. NB. there is a 500 byte limit for Produced/Consumed tags, which can be of any type, except BOOL

For data that needn't be transferred continuously, then the message (MSG) instruction can be used to initiate the data transfer whenever you like. This data transfer can either be "Write" to the destination PLC, or a "Read" from the source PLC. Of course, data transfers using Messaging require the PLC to be in Run mode.

HTH

Thanks, another question is one program for L62 is done by us and another program for L61 is done by others, how can we corporate to download two programs to these different two plcs using procedure and consumer mode?

It will have to be done intentionally - with lots of communication between you and them. You'll have to define what needs to be produced and consumed by which processor -- just like you would do if you were doing it all yourself in-house. Lots of communication, planning, documentation. Intentional design and programming.

Additonal info....

When using Produced/Consumed tags, although not necessary, I always think it a good idea to use the same Tag-Name in both (all) processors. It makes configuration, and data tracing much easier when switching between the two applications.

When using data messaging, I always put the message instruction in the Destination controller, and use a message read. In that way you will always be able to Cross-Reference the destiantion tags, show the MSG, and inspect from where it is reading. If you use message writes, then the destination tags will be changing, but as you x-ref them to see where the data is coming from, you will will not see anything, except where the data is used.