NI USB 6343 Digital / Analog Output

[davidc74]

Good morning, 

I'm working with a USB 6343 with Python3 and nidaqmx lib.

I want to  control a continuous motor and is it correct to control it's speed, rotation direction and of/off like that ? 

(I can set its speed from 0 to 10V) 

Spoiler

def control_digital():

    with nidaqmx.Task() as task:

        task.do_channels.add_do_chan("Dev1/port0/line0") # control ON / OFF

        task.do_channels.add_do_chan("Dev1/port0/line1") # control rotation direction

        task.write([True, True]) #ON / Direction True

        time.sleep(1)

        task.write([False, True]) #OFF / Direction True

        time.sleep(1)

        task.write([True, False]) #ON / Direction False

        time.sleep(1)

        task.write([False, False]) #Off / Direction False

        time.sleep(1)

# Write DO value False / True

def control_analog(voltage😞

    if voltage < 0 or voltage > 10:

        print(f"Incorrect voltagespecified ({voltage}) limits ar 0-10V")

        return False

    with nidaqmx.Task() as task:

        task.ao_channels.add_ao_voltage_chan("Dev1/ao3") # control motor speed (0-10 V)

        task.write([voltage])

        print(f"Voltage set to ({voltage})")

    return True

if __name__ == '__main__':

    for i in range(0,11, 1😞

        if control_analog(i😞

            control_digital()

Now i've got a second question, i want to control another type of motor which can be controlled with sinus waves. 

I can set its frequency and amplitude by sending it a sin waves with frequency/amplitude as paramters. 

I want it to have to following behaviour:

i send it a sin waves, and it keep the parameters untill i decided to send another to sin wave. 

Do you have some clues to help me ? 

Thank's a lot ! 

[davidc74]

Hi, sorry for posting again but i've find a partial solution:

import nidaqmx
import numpy as np
import time
from nidaqmx.constants import AcquisitionType, TaskMode

Fs = 8000
f = 300
sample = 8000
x = np.arange(sample)
y = np.sin(2 * np.pi * f * x / Fs)

with nidaqmx.Task() as task:
    task.ao_channels.add_ao_voltage_chan('Dev1/ao1')

    task.timing.cfg_samp_clk_timing(8000,sample_mode=AcquisitionType.CONTINUOUS)

    print('Generation is started')
    task.write(y)
    task.control(TaskMode.TASK_COMMIT)
    task.start()
    
    while True:

        print("Generating")
        time.sleep(1)

This solution is okay, it's working fine. 

I've got two questions about it: 

I can change the frequency by changing the "f" var.

How can i change the amplitude ? 

And why Fs / sample should be setted to 8000 is it for precision ? I can change those values but the comportment of my motor is'nt the same can someone explain me why ? 

Thank's a lot !