This Ignition system has been running in Production about 6 months now, no problems.
Today I added a String tag element to a Data Type being used for OPC to my PLC.
(This String has existed in the PLC for a long time, just today I wanted to see it in Ignition)
Ass soon as I added the element, all the instances of this data type stopped updating (there are 8 instances total).
Deleting this new element from the Data Type did not fix the problem, none of the tags in any instances of this datatype are updating. Other tags to this PLC are still working fine.
In the Gateway, I tried “Refresh Browse” this driver, no improvement.
I tried turning off Enabled saving, and turning Enabled back on - no improvement.
Tag Diagnostics just shows Value: NULL, Quality: Unknown.
One point of note: when I click a button on a screen that writes to one of these tags, it writes to the PLC OK, shows that it is working, but if I change the value in the PLC, Ignition does not see the change.
In the screen shot below, you can see the buttons under SOURCE and DESTINATION. Source is connected to tag SELS. Under DESTINATION, I clicked the button for MASONRY GUN, it wrote the correct value of 1 to the PLC, but if I change the value in the PLC, the buttons do not notice. See in the tag browser the value from SELD is showing as 1, but in fact it is currently 0 in the PLC.
Ignition 7.9.8, ControlLogix PLC 1756-L72 version 19.