Spent most of today troubleshooting QNAN errors on various I/O modules. We mostly saw them with SNAP-AITM-4i modules, but also had the problem with SNAP-OMR6T-C and a couple others. Then other modules (in Point Config in PAC Manager) would show up as AITM-4i modules! Then other EMPTY slots would show up as AITM-4i modules! It was mayhem. (FYI, using SNAP-PAC-RCK-16 with EB1 and EB2 brains – I saw same problem on two racks.)
After doing lots of unplugging and plugging modules back in to see if we had a bad module, I finally screwed all the modules down. Did at least one full download of the strategy and rebooted (turning power off and then on, not just doing a repower I/O unit command from PAC Manager). It now seems to be pretty stable on both racks that were having the problem. Cross your fingers for me – I will update this if it turns out to be something else.
I think part of the problem was stiff thermocouple wire on the AITM-4i’s, and very little clearance in the rack.
It just goes to show you that you don’t need to screw down modules… /until you do/. I hope this saves some of you a few hours!