Hi
I´m trying to build a simple Recipe system in Ignition (Maker)
I have createt Database/table in MariaDB (MySQL).
To move data from SQL to PLC I have made a Transaction Group
In the the Transaction Group I can not get the Write handshake (PV-status) to function the way I think it should work, it always write “OK”, both when the PLC orders a legal and a non-legal recipe. I think i have understod the Write handshake wrong, but I can not find a “good” desciption of this.
See above screendumps
The handshakes, I believe, are for things that keep the group itself from completing, usually in the Expression items. You’ll need to make a triggered item to handle when a recipe doesn’t exist.
The simplest would be a query with something like:
SELECT COUNT(*) FROM PwrRecipe WHERE PwrID = {[~]SP_PwrID}
If the result is 0, that’s a no-recipe condition.
I think you need to reset the handshakes in the PLC for “next” time. Otherwise, it will stay high after the initial set.
Understood 
& thanks for answer
It make sense what you are writing, but I dont understand how I shall make this! I have done as the above screendump, is that the right way? Is still dont work?
You’re almost there! 
You can write that value back to PV_Status in the Target Name, instead of using the handshakes.
Thank you