Produced/Consumed Tags. Is there a way to check if there is a connection?

I look after the data collection for our plant. At this point I have 75 Rslogix 5000 series PLC's communicating via a uni-cast network to a central PLC that's used as a data concentrator.

The data concentrator is accessed by Factory Talk Transaction Manager to collect and store production data and workcell fault data to an SQL database.

But sometimes these PLC's are turned off. And when they are the consumed data in the data concentrator is held at it's last state. There's nothing to tell me if the PLC producing the data is connected to the network or off.

I have a simple heartbeat system set up using a timer on the producing PLC to send a changing number via a timer to the data concentrator. The data concentrator PLC checks the number sent against the number sent 2 seconds prior and compares them. If the number changes, the PLC is assumed to be on-line. If not, it is, barring any communication issues, assumed to be turned off.

I was wondering if there was another option?

Is there a way to monitor the communication status of consumed tags directly?

I hope I explained this question well enough and appreciate any answers I might get.

Dave

Look into the GSV command - I believe it will give you the ability to look to see if the connection to your PLC's are failed or running. Sorry, I don't have access to the specifics.

Using the GSV instruction to read the EntryStatus of the Module object is what you're looking for. Use the keywords "GSV" and "EntryStatus" to find numerous articles on the topic both here and on the RA Knowledgebase.

What that gives you is the connection status to the remote ControlLogix. It doesn't necessarily reflect the status of each individual Produced/Consumed Tag, nor does it necessarily reflect the state of the controller (Run/Prog/Fault).

RSLogix 5000 v17 and up allow you to define a ConnectionStatus DINT as the first element of a Produced Tag, so you can use that value as a connection monitor.

I use both: I check the EntryStatus every second with a GSV, and I use a rolling counter in one element of my Produced/Consumed Tag or Array Tag as a "runmode with good comms" watchdog.

Problem Sloved

Ken Roach said:

Using the GSV instruction to read the EntryStatus of the Module object is what you're looking for. Use the keywords "GSV" and "EntryStatus" to find numerous articles on the topic both here and on the RA Knowledgebase.

Click to expand...

I checked into your suggestion Ken and found the info I was after. The GSV instruction to read the EntryStatus of the Module object was the answer.

Although I had mentioned the P/C tags, what I really needed was a way to check if the communications between the two PLC's were valid. Your suggestion and a bit of searching on the RA Knowledgebase gave me the answer I was looking for.

Sometimes it takes but a push in the right direction by someone with a bit of background on the subject to help a person find the info they need on their own. And in the end becomes a great learning experience.

Thanks for everyone's suggestions. It helped out a lot.

Dave