Is it possible to read from the NIDAQ card's clock system using Python?

[strong-dare-45]

I'm new to the nidaqmx library, and I was wondering if there is a way to read from the default sample clock in the NIDAQ card? I want to do this to figure out the time it takes to collect a particular number of samples. Any responses/solutions would be much appreciated!

What I tried:

I tried using the time/datetime modules in Python already, but it doesn't seem like a very accurate way to measure the (elapsed) time it takes to collect samples. For example, If I use that to find the time it takes to collect 10 samples at 10Hz, the output would be 1.02 seconds rather than 1 second.

I've also tried accessing the default clock through the methods in the nidaqmx documentation and searching in the stackoverflow/ni community discussion forums, but I still have difficulties finding a way to actually get outputs from the clock.

[strong-dare-45]

I also just wanted to add that the NIDAQ number is USB-6345!

[santo_13]

Sample clock is something you configure, but what you configure is coerced by the driver to a value what the hardware is capable of and supports.

next, if you collect 10 samples at 10Hz, the data collection completes in 1s on the dot but there are overheads in the drivers to transfer that data from hardware to the functions and so on, so it is never exactly 1s at the software layer.

[ZYOng]

DAQ device only stores the t0 value when the task is started. See Accuracy of the Waveform Timestamp Returned by NI-DAQmx

Usually, you just need to read the data as a waveform and it will contain the timestamp of the data point. Unfortunately, DAQ python API does not expose the read API which returns waveform data. As an alternative, you can first configure the TDMS logging and then read the TDMS file to get the timestamp. See my examples in python-ni-examples/nidaqmx_examples at main · ZhiYang-Ong/python-ni-examples

[n7j]

I will also say that there is a property to pull the system clock from Python for a given task.

It is the property named: nidaqmx.task.Timing.first_samp_timestamp_val

For cDAQ-9185/9189 and other PTP enabled DAQs, this value is the PTP timestamp.