Hi all,
I am using Python 3.10.14 with NIDAQmx 0.9.0. I have a motorized stage, which I control via the serial port in my Python script. The stage is programed to output a trigger at the start of its movement. I want to use this trigger to start my data acquisition. I have a code that works, but I feel I'm over-complicating things and I'd like to have a second opinion.
In my code, I'm using the threading module. My idea is to start the DAQmx task (reading 6k samples in two analog input channels) in a separate thread, such that I can keep control of my stage, which ultimately sends the trigger. So, I defined a function to arm my DAQ (USB-6002 for reference):
import threading
def arm_daq(data):
with nidaqmx.Task() as task:
task.ai_channels.add_ai_voltage_chan("Dev1/ai0:1")
task.timing.cfg_samp_clk_timing(rate=25e3, samps_per_chan=6000)
task.triggers.start_trigger.cfg_dig_edge_start_trig("PFI0")
data[:] = task.read(number_of_samples_per_channel=6000)
Then, in my main program, where I control the movement of my stage, I start the thread such that the DAQ becomes ready for triggering, and then I send the commands to move my stage:
if __name__ == "__main__":
data = np.zeros((2, 6000))
t1 = threading.Thread(target=arm_daq, args=(data,))
# Instructions to move the stage
t1.join()
Note that the data array is modified in-place within the thread and will be available in the main code automatically.
As I said, this works fine for me, but I have to commit a thread for the DAQ. And this is the reason I think I am over-complicating this. I thought the very idea of a DAQ was to offload the "processing" to a separate board (the DAQ). Can someone share their experience on this task? Is it how you'd program your DAQ as well?
Thanks for your help and take care,
David
