I have a group that has one OPC item. I have it so that the OPC item updates a row in a table only when a change has occored and the update rate is 500ms. the problem i have is the value in the data base is a float and when the scale is turned off the value in the opc item is E_FAIL. how do i stop the group from updating when the value is text?
Here’s what I would do:
- Make a copy of the item in the group (just copy/paste that item).
- Double click the copy to edit it, make the following changes:
- Set “Property” to “Quality”. Data type should become integer.
- Select “Read Only”
- Change the group’s trigger to use the new quality based item. Set the trigger condition to the 3rd condition option, “Active = 192”, “non-active != 192”
- At the top of the trigger pane, select the first check box “only evaluate this group when a change has occured”
So basically, you’re just telling it to only execute when the quality is good. The “async update” option maintains your functionality of only logging when the value changes.
Hope this helps, let me know if anything isn’t clear!