At our plant we have mostly AB PLCs, but in one area we have some Modicon PLCs. The AB should send info (i.e. weight, product code, etc.) to the Modicon. The DH+ connections are all good, but from time to time we will lose some of the info and that causes us problems in our product flow. Could it be that the data from the AB PLC is not understood by the Modicon PLC, or could there be some other reason? HELP!!!

 

I am not real sure just what you are saying. DH+ has absolutely nothing to do with anything Modbus.

Most of the time when I hunt down these kinds of problems it turns out to be some kind of software error, usually related to some kind of unexpected situation that the code did not respond to in a desirable way.

 

Which Modicon PLC have you?
Maybe you need simply a gateway.