At 7:45AM one of our Micrologix PLC’s started throwing around 500 of the above mentioned errors a minute until 9AM when I disabled it. I have had PLC’s give me No route to host and many general errors that lead to telling me to ‘take a hike’, but I have never seen this error. After having the network cable repunched and both ends redone. I try again and still get a Null data error. We reboot the PLC and our Ignition server and still get the error. I think maybe the PLC dropped it’s program. It didn’t. 
I remove the configuration for the PLC and redo it. and still get the error. Extra info: the device shows up as if it is perpetually connecting on the device page and only shows as disconnected when turned off. Usually my devices flip back and forth when trying to connect. Thanks for the help
erfritts, is this a direct connection or is it going via a chassis or similar? If so, has connection path changed and does it need to be updated?
Could you take a Gateway log export and attach it here so we can take a look?
Thank you for your reply Anna. Sorry it took me a while to get back to the forum I got sent home for a few days with a cold. So here is an update. This was quite befuddling. A day later Ignition disconnected itself from our local DB, source of all it’s knowledge and crashed. After about 3 reboots it was willing to speak to the DB again. (I was home sick) My boss finally determined that one specific HMI was hammering the DB for data for a chart. I from the beginning have been using the client date time tag to get data for my charts. This was no problem when the client was properly setup with NTP services. This particular client was new and somehow made it to the floor without NTP installed and when there was a power outage it set it’s clock for 2012. So every time they opened the diagnostics page the realtime chart would try to draw 5 years of data from the DB. The problem child PLC was the most obvious symptom but it was not the cause it was just ignition try to dump some load. The particular PLC is the least used. We also got Hour and Minute tag errors everywhere, etc., etc. So The take away protect yourself when using realtime charts and use the Gateway date time system tag NOT the clients.
Thanks again for the reply Anna