Simple Design Question


I have a newbie question:

Whats the best way to keep the DB and a Tag in sync given this: I have a Set-point stored in the PLC and also in the database. I also have a Vision window where the user can change the value of the set-point. I also have the concern that if the PLC power supply fails I can lose the value of the set-point but if it’s stored on the DB it can be recovered. so, what should I do:

I have thought of these options

  1. Bind a screen numeric input to the tag and add a script to update the DB
  2. the numeric input stores the data in the DB and a SQLBridge transaction updates it to the PLC
  3. the numeric input writes to the tag and a SQLBridge transaction updates the DB (but would this work when the PLC loses the set-point?)

Any guidance will be very appreciated

In this case it would be best to have a DB tag in a standard transaction group that is set to bi-directional OPC wins mapped to the right database table. Ignition will take care of synchronizing the two. You only need one group.

Thank you Travis,

And the numeric input would be binded to the DB tag?

Right :slight_smile:

Thank you Travis. It worked like a charm! :thumb_right: