# OPC Server tag Produced/Consumed **URL:** \ **Category:** Ignition\ **Tags:** ignition81\ **Created:** [October 30, 2024, 8:53pm UTC](https://forum.inductiveautomation.com/t/opc-server-tag-produced-consumed/97976 "2024-10-30T20:53:09Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![B\_Graham](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@B\_Graham](https://forum.inductiveautomation.com/u/B_Graham)\ **Post date:** [October 30, 2024, 8:53pm UTC](https://forum.inductiveautomation.com/t/opc-server-tag-produced-consumed/97976/1 "2024-10-30T20:53:10Z")
Looking for some help with the best path forward. Ignition 8.1.43: Have OPC Server connection in addition to the Ignition OPC UA Server. This is the OPC for a CMM (coordinate measuring machine) I am working integration on. With this connection I now have the desired tags exposed on the CMM side for my project. I also have a PLC that controls the automated cell, separate from the CMM. I am wanting to understand the best method to create two way communications, through OPC for the CMM and PLC. Example: Wanting a Run Complete status to be shared via OPC. The run complete bit would be generated via program on the CMM side, read via opc to ignition, then write via opc to PLC, then, once PLC ack, reset bit. Obviously, there are ALOT of ways to go about this, but wanted some advise. Some options thought of: Gateway event script evaluating CMM tag for change, then updating PLC tag. Possibly an expression tag somehow. Gateway script to Map IO. Send all of the CMM OPC tags to PLC and map the IO that way. Seem to be rambling on at this point! Long day! Thanks for any input! ---
**Author:** ![B\_Graham](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@B\_Graham](https://forum.inductiveautomation.com/u/B_Graham)\ **Post date:** [October 31, 2024, 3:34pm UTC](https://forum.inductiveautomation.com/t/opc-server-tag-produced-consumed/97976/2 "2024-10-31T15:34:13Z")
Found a great link discussing what I am wanting to do. Still open to any ideas. Thanks again! > [@Read from A OPC device, write value to B OPC device/PLC](https://forum.inductiveautomation.com/t/read-from-a-opc-device-write-value-to-b-opc-device-plc/49325): > > Hi everyone, I’ve got a customer that wants to use Ignition as a middleware between OPC systems (A device and B device) on a production line. Ignition is to read values from OPC device A and then write changes into a PLC or other OPC device. My first thought was just to have tag event change scripts on the tags to write whenever a change was registered. My only concern is that there will be a lot of tags being managed all at the same time. For instance, a device could have hundreds of tags and…