I’m looking for a way to mirror tag values between two Ignition Gateways without having to use Gateway Event Tag Change scripts. My setup is roughly as follows: Gateway 1 is connected to PLC 1. PLC 1 has 10 tags representing the ON/OFF state of 10 part-present sensors. Gateway 2 is connect…

Disclaimer: This is a really bad idea--Ignition isn't really designed to do this. PLCs should be using native technology, like producer/consumer tags in Rockwell, to do this kind of process synchronization. So your SCADA system stays in supervision, not directly in the control loops. If you must…

Thank you for the suggestion and warning :sweat_smile: I was not aware. We do try to keep all sorts of control away from our ignition systems as much as we can. In this example, the reason we resorted to having to do it this way is because a PLC to PLC connection was not able to be established, so …

If you want to do this natively then: tagA value change script that writes its value into tagB scheduled gateway event with a script that runs periodically that has your list of tags and does a compare against the two values and if there's a difference rewrites tagA into tagB. Both are necessary …

Thank you, i will mark this as the solution for now. If i encounter any issues i can return to this thread.

[image] AdrielP: In this example, the reason we resorted to having to do it this way is because a PLC to PLC connection was not able to be established, I would look harder into this and try and do it the right way, if at all possible. Why is PLC-PLC connection not available? How are the gate…

The factory where we integrated our solution has separate networks and this machine in specific is technically not allowed to talk to devices outside its network (because IT said so). It was not our decision to make and this was the way they determined it needed to be done. We are integrators, we d…

Okay, so they must have a managed connection of some sort that allows the gateways to talk across the networks but not the PLCs. I'd make them aware that if the Ignition server for machine 1 is shut down for whatever reason, even if the other machine is running, this data would no longer make it to…

[image] AdrielP: because IT said so This is the kind of decision path that gives IT a bad name. They've chosen to connect production systems to each other across networks using a very generic technology with opaque traffic instead of using the appropriate vendor-specific protocols (that show…

Mirroring Tag Value Across Gateways

Ignition

pturmel September 17, 2026, 2:48pm 6

It is a free (but not open source) 3rd party module. Found through the IA Showcase or directly from my website. I suggest you start here (read the whole thing):

This may also help:

Probably not, as it targets OPC items in the same gateway as the source tag--it cannot work across the gateway network. But a bulk script can assemble a bulk write to tags in a Remote Tag Provider.