PyDAQmx and USB-6000/USB-TC01 Thermocouple Device

[pyfreak]

Hello all, 

I am thinking of purchasing the same device for an application of my company. Can somebody verify that the code works/works as supposed?

[Andr3s_Br3n3s]

Here are some useful link that can work for you in the future about

PyDAQmx

https://pythonhosted.org/PyDAQmx/usage.html

This GitHub page is awesome, a lot of examples  https://github.com/ni/nidaqmx-python

Here is an official white paper http://www.ni.com/white-paper/53059/en/ about    NI and Python Resources

Here is a really good pdf https://media.readthedocs.org/pdf/nidaqmx-python/latest/nidaqmx-python.pdf 

have a great day.

[Andr3s_Br3n3s]

I conflated the two versions, 

One is PyDAQmx  and the other is NI-DAQmx  Python API 

[pyfreak]

Hello,

I tried to run the script given but I get the following error:

    sensor = NiUsbTC01()
  File "nitc.py", line 33, in __init__
    self.nidaq = ctypes.WinDLL(nidaq_dll_path)
  File "C:\Python35-32\lib\ctypes\__init__.py", line 347, in __init__
    self._handle = _dlopen(self._name, mode)
OSError: [WinError 126] The specified module could not be found

The reason is that I don't have the nicau.dll. How can I get it to run without installing all the nidaqmx runtime?

Cheers!

[J3ronimo]

Unfortunately, you'll indeed need it. Use the commented-out line:

self.nidaq = ctypes.windll.nicaiu

My code from above is incorrect for that matter, since using only the one DLL doesnt work, which I hadnt realized before I tested it on another machine where the runtime wasnt installed.

I also tried to walk down all the dependencies, hoping it'll be just a couple of DLLs that I'd have to add and that it would be portable, but no luck, I finally gave up. But let me know if you can come up with something, it's quite annyoing that you have to install a whopping 300MB software bundle to be able to read out a simple temperature sensor...

[EleniVlachou]

Hello all,

In order to run the python script you have to include the absolute file path of nicau.dll (mine is "C:/Windows/SysWOW64/nicaiu.dll").

I attach the code.

[AranelMalina]

Hello All,

Python nidaqmx does support logging from the USB-TC01 thermocouple as task:

import nidaqmx
from nidaqmx.constants import TerminalConfiguration
import time
import threading
import keyboard

from datetime import datetime

start: bool = False
period: float = 0.1 # every 100 ms ??
logTimeInMinutes: int = 1

def measure_thread(taskDev, devName):

    now = datetime.now()
    fileName = now.strftime("Thermal_Log_%d_%m_%Y_%H_%M_%S")
    print(fileName)
    directory = "Log/"
    fileHandle = open(directory + fileName + ".csv", "w")
    fileHandle.write("TimeStamp (ms), " + "TotalMinElapsed (min), "
                     + "Temperature (F) " + "\n")

    global start
    global period

    startTimeInMs = time.time()*1000
    lastMinElapsed = 0


    while start:
        # timeStamp = now.strftime("%d:%m:%Y:%H:%M:%S , ")
        timeStamp = time.time()*1000 - startTimeInMs
        # 60 seconds in a minute, 1000 ms in a second
        TotalMinElapsed = timeStamp/(1000*60)

        #in Hours
        SegmentHourElapsed = (TotalMinElapsed - lastMinElapsed)/60


        samples_per_channel = 10

        data = taskDev.read(samples_per_channel)
        print(f"{data}")

        SampleAvg = sum(data)/len(data)

        print(f"{SampleAvg}")
        strToWrite = (f"{timeStamp:.3f}, {TotalMinElapsed:.6f}, {SampleAvg:.3f},")

        fileHandle.write(strToWrite + "\n")
        time.sleep(period)
    fileHandle.close()

def main():
    global start

    devName = 'Dev3'

    with nidaqmx.Task() as ThermoTaskDev:
        ThermoChannel = ThermoTaskDev.ai_channels.add_ai_thrmcpl_chan("Dev3/ai0",
                                             name_to_assign_to_channel="Thermocouple",
                                             min_val=0.0,
                                             max_val=100.0, units=nidaqmx.constants.TemperatureUnits.DEG_F,
                                             thermocouple_type=nidaqmx.constants.ThermocoupleType.K,
                                             cjc_source=nidaqmx.constants.CJCSource.BUILT_IN)

        while start is False:
            value = input("Enter 's' to Start: ")
            if (value == 's'):
                start = True

        threadHandle = threading.Thread(
            target=measure_thread, args=(ThermoTaskDev, devName))
        threadHandle.start()

        while True:
            if keyboard.read_key() == "q":
                start = False
                break

        threadHandle.join()


# Press the green button in the gutter to run the script.
if __name__ == '__main__':
    main()