Error 200302 in DAQ-mx global virtual channels when reading 0Hz

[JRoe]

Hello, I am attempting to calculate flowrate via frequency (by counting the pulses for a given time).

The frequency read seems fine when the operation is running. However, when there is no flow (only tested by reading the channel with the operation off) there is an error 200302 (Signal being measured is slower than the specified measurement time.Increase the measurement time, or use a different measurement method.).The concern is to make sure that when there is actually no flow rate while operating that the returning information is confirmed to be valid.

So far the only solution I've found is just ignoring/hiding errors. Any further help would be appreciated and if I have not been thorough enough please let me know.

Thank you for reading.

[dkfire]

Witch hardware are you using ?

[BROhan]

Hi JRoe,

In hardware, reading 0Hz could be confused with not reading anything (which could lead to a timeout). Therefore, it is most likely going to be necessary to handle/ignore the 200302 error that is thrown.

[JRoe]

Thank you for the responses.

The DAQ hardware being used is the PCI-MIO-16E-1.

If there is any confusion please let me know.

[BROhan]

Hi JRoe,

Even with that card, you will still have to handle the error and create an exception for it, as it will be considered a timeout since nothing is actually being acquired.

[HeatherBaker]

Hi JRoe,

You can change the timeout to -1 where no timeout will occur and consequently no error; however, until a sample is read the DAQmx Read will wait before progressing onto the next while loop iteration.  This is another option to consider in addition to handling the error exception.