what would clear alias names in NI-MAX?

[mysticfree]

Last night, a storm knocked out power to our manufacturing facility.  We were able to get all testers back into production except for one.  After a little troubleshooting, I found that the alias names in NI-MAX had been cleared.  Once I reentered the names, all worked well.

I was wondering what would have cleared out those names in the first place?  Has anyone had this happen?

[Kyle97330 · Accepted solution]

Aliases for NI-MAX should be stored here:

C:\ProgramData\National Instruments\NIvisa\visaconf.ini

In it, there will be lines that look like this:

Alias0="'COM1','ASRL1::INSTR'"

So either something went wrong with that file and NI-MAX had to re-create it, which will erase all aliases but fill in everything else with defaults and detected hardware, or something caused some/all of your hardware to be detected under different addresses so the aliases remained in the file but were no longer applied.

The second one I have only ever seen in cases of cheap/counterfeit USB-to-serial adapters that would sometimes give themselves new COM port numbers, but I can't rule out it happening for other reasons.

It seems more likely to be the first one, where the file was cleared or otherwise restored to defaults, because NI-MAX should throw up a dialog box if you attempt to add an alias that already exists, even if the already-existing alias is assigned to hardware it can't detect at the moment (since it assumes it's something that could get plugged in later and would want to give it its old alias back).

I don't know why specifically the file would disappear from a power outage.  If possible though, you might request UPSes for your test station PCs.  They don't need to be very powerful, just enough to keep the PC running for ~5 minutes and that send a signal to the OS to shut down when they only have ~2 minutes of battery left.  You actually got lucky to only lose aliases, we lost a motherboard on one of our stations and finding a replacement was a lot harder than it should have been and we were down for 3 weeks.

[mysticfree]

Thanks, Kyle!  Since the plant is plagued by power outages during summer storms, all of the testers have a Cyberpower UPS.  Although, the UPS on one tester in question has been in service for almost 4 years now.  The backup power "says" it has 30-minutes of AC but I don't know if this is true.  I'll need to review Window's event log to get a better idea of what happened.

NI-MAX showed the Keysight DMM and the USB-8451 with blank names.  We communicate to a Telesis marker through a serial-usb converter and - just like you said - that converter had lost is COM port reference.  Once everything was renamed, all was well in the production world.

Thank you again for the vital troubleshooting info!