I am using two Sparkfun FTDI Basic breakout boards to send receive data via UART. Yesterday, everything seemed to be working fine and I was successfully transmitting and receiving. Today, I changed a few minor and irrelevant things in my code, briefly had the USBs unplugged, and now it suddenly seems to be saying 'no thanks' and not cooperating.
I've read through the various similar discussion forum posts, however, it seems that while this is a somewhat common issue, the solution is heavily dependent on the device(s) being used.
When I open NI-MAX and create a test panel for one of these devices, I am able to write the default data (*IDN?\n) but as soon as I try to read status bye or read the data I get the following error messages.
1. Read STB Operation
Error
VISA: (Hex 0xBFFF003A) Unable to start operation because setup is invalid (due to attributes being set to an inconsistent state).
2. Read Operation
Error
VISA: (Hex 0xBFFF0015) Timeout expired before operation completed.
It looks like the device attribute "is port connected" is an invalid property node. Perhaps this is because it is not an NI-serial device? Does anyone have any suggestions for how I can eliminate this property node both in NI-MAX and in my VI? Unfortunately, the VISA configure function does not contain an input for "is port connected" which begs the question as to how one can delete dependency for this device attribute.
At this point, my troubleshooting has consisted of trying out some of the other USB ports on my USB hub. I've also verified that the 'COM' port that windows is using for the device matches up with the COM port that NI-MAX is assigning.
Thanks for the help