I've been debugging this issue for some time and cannot find a reason to explain why.
I am using a cDAQ-9178 with eight slots. Three slots are thermocouple (TC) cards, 9213 and the other two are a voltage and current card, 9375 and 9208 respectively.
Two loops are reading the different cards depending on the data type. One loop monitors the voltages to count pulses from flow meters, the second reads the TC and current cards.
The voltage loop continuously counts falling edge pluses and loads the total onto a queue every second. When the voltage loop triggers a total to be loaded, a notifier trips the bottom loop to record the TC and current reading.
The code is continuously running and dequeuing elements that are sent to a database table, where a new row is generated with the newly recorded data.
Around the same time, been this way the last two days, the DAQmx read vi will freeze and does not trigger the timeout error. When opening the code and using the highlight operation, the code shows green arrows on the two DAQmx read vi's in the bottom loop. See the screen shot of the bottom loop below. (Sorry don't have a screen shot of the actual frozen code)
As I said, this has happened the last two days at around 4:30 am. The strange thing is, I cannot stop the code from the main front panel because any controls are not registered by the main vi due to the fozen DAQmx read vi.
I can either unplug the cRIO which allows the front panel to be read, and upon shutdown, an USB communication error pops up. If I am not at the PC, I have to restart the computer to restart the code. Otherwise, if ctrl-alt-del is used to shut down the main vi, upon restart, the system cannot recognize the cRIO being connected to the PC, and hence must be shutdown.
Any advice or steps to help debug the issue would be great.
Thank you in advance for any help, I've been left scratching my head what the problem could be.
Memory limition on the PC or cRIO or the USB connection is too slow. The strange thing is, the code works well 99% of the time.
I've attached the two main vi's that should cover the scope of the problem.
