05-23-2016 01:51 PM
I am new to LabView and a friend built this system for me to measure output from a thermocouple card. The only problem is that nothing appears in the plot. The output from the DAQmx is wired directly to the graph, so I don't know what the problem is. There are no errors.
I have the DAQmx set to Analog>Single Channel> Multiple Samples> waveform.
05-23-2016 02:00 PM
You should call the DAQmx Timing VI before starting the task. With that VI, you set the sample rate (I fairly important thing to have). Also make sure the task is set up to be Continuous Sampling. I would also recommend getting rid of the wait in the loop and instead tell the DAQmx Read to read 1 second's worth of data (based on your sample rate). And if you want to keep a history (more than just your 1 second's worth of data), use a Chart instead of a graph.
05-23-2016 03:27 PM
Thank you for your reply. I am confused about your suggestion, however. I added a timing VI and set the sample rate to 3. I see no option anywhere for continuous sampling. I got rid of the wait as you suggest and started using a chart. I ultimately want to use the graph to monitor but have the results written to a file.
This new setup runs without error, but still no plot.
05-23-2016 04:13 PM - edited 05-23-2016 04:14 PM
first test your Daq with test panel and ni max if you do not find any error
After that you can check your code in labview for find problem also 3 sample rate is so slow data rate try to use with a bit more sample rate for test
05-23-2016 05:09 PM
Help > Find Examples... Browse tab > Hardware I/O > DAQmx > Analog Input > Thermocouple - Continuous Input.vi