Guys I have several transaction groups set up to record some barcodes. The setup is one OPC tag in the transaction group, I then have an expression tag setup in run always. The expression tag is used to trim off some characters at the start and the end. This expression tag has a target write to another tag.
I then have 2 tags setup in triggered expression pane, 1 tag that has a static location that never changes and the other is written from the expression tag above (barcode trimmed). This tag has a database target so I can capture the barcode to SQL.
I have an update of 1 second and I have checked the ‘only evaluate whe vales have changed’, set to look at the run always tag when it changes.
For the most it works but I do get double recordings in the database, I do think sometimes I am missing some barcodes that are being replaced by the last reading. It apears that the OPC tag is getting the value all the time but the result in table can be double reading.
Can the execution timing be out somehow? What do you think??