Essentially, some PLC UDT instances went missing from the Ignition device browser and the connected SCADA tags stopped working after an alleged power blip. I got them working by editing the PLC UDT online and refreshing the device browse. Now I'm wondering why this happened and what I can do to prevent it from happening again. Here are the details:
Our client has an Ignition 8.1.16 gateway with an OPC UA device connection using the standard LogixDriver to an Allen Bradley 5069-L340ERP CompactLogix 5380 (firmware version 34.01). Device driver configuration was standard, just IP address and slot 0. The device connection has been working fine.
A couple weeks ago, the power supply for the PLC had a discharge light on. When troubleshooting, site maintenance informed us of a power blip, plantwide by the sound of it (affecting PLC, SCADA PC, network switches, and field devices).
A couple months ago, I imported a PLC UDT definition for an analog input UDT that included some alarm setpoints, alarms (1x nested PLC UDT instance), scaling (1x AOI instance), and a current value. I created 5x instances in this PLC, each representing a transmitter, and created instances of a corresponding Ignition UDT. These communicated fine for a couple months until the power event, when the tags read in with bad quality ("Error_Configuration" showed up in the tag browser, and "Bad_NodeIDUnknown" when I drilled down as I recall). When I opened the Ignition device browser, the 5x UDT instances were absent, even after refreshing. Nothing else appeared missing from the browse. The PLC UDT instances still existed online in the PLC, there were no apparent issues with these PLC tags, and there were no code changes in Ignition or the PLC that I am aware of.
Some instances of this same UDT in another connected CompactLogix that had been around for a little longer were still working after the power blip.
I went onsite to troubleshoot a week or two ago. I found this forum post: ControlLogix PLC tags not showing up in OPC browser - Ignition - Inductive Automation Forum. Different Rockwell PLC and Ignition minor rev, but an online edit of the UDT instance (changing description) and a device browse refresh fixed my tags.
Anyone know why this happened and how I can keep it from happening again? Linked forum post mentioned a firmware issue. If this is a firmware issue, is it on the AB or Ignition end?
Don't have wrapper logs and don't want to make a special trip to client site to get them, so this is pretty much all the info I have.