chepox

So the issue is the trigger is not fast enough? I also have a raspberry pi 3b that had the sensor connected to it and was working fine when all of the sudden it stopped working. I used the USB 1208LS to try and see if the raspberry was the problem. Now, I do not need to measure the echo pulse width. Just to time the response from trigger pulse until I get a high signal incoming from the sensors echo pin. So there is no way of getting a 10uS pulse out of the USB1208LS? I am changing the bit to high and then low to create the pulse using a timer: ul.d_bit_out(board_num, port_out.type, bit_num_out, bit_value_high) time.sleep(0.00001) ul.d_bit_out(board_num, port_out.type, bit_num_out, bit_value_low) So its not changing fast enought??

I have a simple connection to an ultrasonic sensor (HC-SR04) connected to an USB 1208LS, I have tried 5 different sensors from different manufacturers and have had no success on getting them to work so I can mostly rule out the sensors. The connection diagram is very straightforward and is as follows: PortA Channel 0 -> Trigger pin#21 PortB Channel 8 (or per documentation PortA Channel 15) -> Echo pin#39 Vcc = 5V coming from pin #30 Gnd coming from pin #40 Here is my python script to run a the sensor. I took mostly from this site and adjusted for the USB-1208LS. import time from mcculw import ul from mcculw.enums import DigitalPortType, DigitalIODirection from mcculw.device_info import DaqDeviceInfo from console.console_examples_util import config_first_detected_device board_num = 0 dev_id_list = [] config_first_detected_device(board_num, dev_id_list) bit_num_out = 0 bit_num_in = 15 bit_value = 0 daq_dev_info = DaqDeviceInfo(board_num) dio_info = daq_dev_info.get_dio_info() port_out = dio_info.port_info[0] port_in = dio_info.port_info[1] ul.d_config_port(board_num, DigitalPortType.FIRSTPORTA, DigitalIODirection.OUT) ul.d_config_port(board_num, DigitalPortType.FIRSTPORTB, DigitalIODirection.IN) def distance(): # set Trigger to HIGH bit_value_low = 0 bit_value_high = 1 StartTime = 0 StopTime = 0 ul.d_bit_out(board_num, port_out.type, bit_num_out, bit_value_high) time.sleep(0.00001) ul.d_bit_out(board_num, port_out.type, bit_num_out, bit_value_low) # save StartTime while ul.d_bit_in(board_num, port_out.type, bit_num_in) == 0: StartTime = time.time() print(f'Echoe = 0: {StartTime}') # save time of arrival while ul.d_bit_in(board_num, port_out.type, bit_num_in) == 1: StopTime = time.time() print(f'Echo = 1: {StopTime}') # time difference between start and arrival TimeElapsed = StopTime - StartTime # multiply with the sonic speed (34300 cm/s) # and divide by 2, because there and back distance_traveled = (TimeElapsed * 34300) / 2 return distance_traveled if __name__ == '__main__': try: while True: dist = distance() print (f"Measured Distance = {dist:0.1f}") time.sleep(1) # Reset by pressing CTRL + C except KeyboardInterrupt: print("Measurement stopped by User") The script endlessly loops on "while ul.d_bit_in(board_num, port_out.type, bit_num_in) == 0:" so it seems that the echo never receives the HIGH value back to exit the loop. Output: I have no idea what could be wrong. Does anyone have an idea on what I might be doing wrong? I have already tried to troubleshoot this over and over with no success. I would greatly appreciate any help.

Thank you so much for your response. I was almost sure of that same conclusion. I am now acquiring an amplifier that is not a converter so that I can continue to feed into the Analog Channel. Any recommendations on voltage signal amplifiers?

Do I need an amplifier for the load cell or would the USB-1208LS analog input channels be able to measure the micro voltage changes? Below is my wiring. Connecting to the DAQ are AI Channel 0+ and AI Channel 0-. Excitation voltage (5V) is coming from Terminal #30. The change in voltage is minimal when load is applied to the load cell.

Yes. This worked. I used an independent 16V power source and now I can see the full extent of the wire sensor. Calibration is not an issue for my project since I am importing the data into wit Python script and I can correct values programmatically. Thank you for your help!

I have a 2 wire encoder that outputs a 4-20mA. Excitation voltage 5V Channel 30 is applied to RED from encoder. Black is connected to a 240ohm resistor. Resistor is connected to GRND (Channel 3). Resistor also connects to Channel 1 for voltage input. Channel mode is Single-Ended. Voltage seen on Channel 1 is 0.76V. Encoder only increases the voltage up to 0.86V and then it stops. Is this a bad sensor? or is there something wrong with the wiring? Encoder is an CWP-S500A.