Ignition - copy data between OPC tags

Ignition 7.9
Siemens S7-1200 PLCs

Hi All.

For a few of the machines on my network, I wish to be able to monitor a “heartbeat” signal and then send this to a supervisory PLC.

I already have OPC tags setup for a 1Hz bit on each of the machines to be monitored.These tags are monitored on a “fast” scan. My plan was to setup a series of OPC tags in the supervisory PLC and have ignition copy the data between the OPC tags.

I’ve just rigged up a test with an expression tag copying data between the OPC tags. This seems like a lot of work. Can anyone suggest a more elegant solution please?

Note (AFAIK) the S7-1200 PLC has no OPC client functionality. I could of course set up a direct communication path between the PLCs in question. The Siemens GET/PUT works great for this. However, I was hoping to do it all in ignition!

Thanks for looking


So, using the tag events, value changed trigger for the machine heartbeat tag, I can copy the data to another tag using the following script.

system.tag.write("[~]SYSTEM/Test life bit", currentValue.value)

Is this the best way to accomplish the desired functionality?

Do you have the SQL Bridge module (transaction groups) installed? Syncing data (easily) between PLCs was one of the original reasons the module was created. You can set up a group to read from OPC items and send those values to other OPC items - and, no code required (easy maintenance).


Sorry for the slow response. Yes, I do have this module installed. Is there an easier way to achieve the desired functionality? I basically need to send a “heartbeat” signal from 5 PLCs to one PLC. All the PLCs are already linked to ignition for visualization and SQL data logging purposes.