Delayed acquisition NI 9212

[Lucie.pi22]

Hi everyone,

For our Project we have to make a big acquisition with three modules in a cDAQ and save data in a .xls file. One of them is a thermocouple one, the NI 9212 (used with NI TB-9212) for K-type thermocouples. We want to measure at 2Hz max

The problem we face is quite the same as in this post : reading the thermocouple ports takes too much time compaired to the sample rate, resulting in delays so we don't measure at the sample rate we wanted, no matter the sample rate.

I understood we have to reduce the loop execution rate to minimize the problem, but we tried and testing the same program replacing the NI 9212 module with the NI 9211 ( T-type thermocouples) : this time we had no delays at all.

Here below the code part corresponding to the thermocouple measuring.

Regards,

Lucie

[GerdW]

Hi Lucie,

what's the point in setting a target time of "1e-60" in the elapsed time functions?

What's the point in constantly creating and killing DAQmx tasks? This will take much more time than the actual data reading!

Try something like this:

(Using just one task for both channels…)

Both modules support different kind of thermocouples, you can measure type K and T with both of them!