Simple Design Question

Ignition
1

Hello,

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

2

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.

3

Thank you Travis,

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

4

Right :slight_smile:

5

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