Hi all,
I found out that a client was having some problems with their compactRIO 9148 system, which has NI 9871 serial module in it. Serial comms had been working fine, but apparently, without any changes to software, they started getting VISA errors.
So I check it out, and I see this error is getting returned:
-1073807346
Possible reason(s):
VISA: (Hex 0xBFFF000E) The given session or object reference is invalid.
Fair enough--- let's make sure that the resource selected is valid it is:
visa://192.168.1.200/ASRL1:INSTR . The cRIO is pinging back from that IP address, I can see the serial ports in MAX. Why isn't it happy with this visa resource name?
Probing the actual offending VISA wire, I could see that labview was indeed not considering a valid resource for some reason-- before I even do anything with the resource like initializing the serial port-- the "is instr" led was off. ?!?! Makes no sense.
I went into MAX , and opened up the cRIO under remote systems, expanded the serial ports, and I gave the cRIO COM1 port the alias "MOTOR". I select this alias as the VISA resource, run the program and bam-- it works. I later learned that I was not the first to see this.
I am not sure on how to reproduce the problem. Putting serial cards in an Ethernet cRIO probably is not something you see everyday l know there were some issues with getting software to operate the cards in scan mode in the past years, and the bug with the FPGA nodes lacking terminals in LV2012, so maybe we are in the wilderness. Still, anyone have an idea or two?
