Connecting Flow Sensor to USB 2416

[Mackenzie Cox]

Hi I bought this flow sensor:
https://www.instrumart.com/products/45963/eh-picomag-electromagnetic-flow-meter

Part number: DMA20-AAACA1

Here is the manual:  https://www.instrumart.com/assets/Picomag-Manual.pdf

 

I want to connect the sensor to my USB 2416 so that I can read a voltage off of it on daqami. I cannot get it wired correctly to give me the correct voltage based on the scaling. Can you give me some guidance? I have the blue wire connected to 18V- and the brown to 18V+, which I am pretty sure is correct since the flow meter is working at the screen on it is reading the right value, I just need to know how to connect the white and black wires to the USB 2416 to get the readings on my computer.

 

Thanks

[JRys]

I glanced at the user manual, and you can use either the IO1 (black) or IO2 (white) output. The outputs are programmable, so you have to use the Bluetooth interface to program one of them as a voltage output. (The manufacturer would know better.) Because it's fundamentally a 4-20mA current output, it internally connects a 500-ohm resistor between the IO and 18V-. This is because it outputs 2 - 10 volts, and if you use Ohms Law, 2mA through 500 ohms is 2 volts, and 20mA is 10 volts. If current is selected as the output, you must supply your own 500 ohm resistor to get 2 - 10 volts. Please check what I said with the manufacturer.

The next step is connecting it to the USB-2416. Connect the white wire to the input's H terminal and the L to GND, assuming the USB-2416 input is set to differential and not single-ended. Connect the sensor's blue wire (18V-) to GND. You should remove your other sensors to test if it's working. 

[Mackenzie Cox]

I removed all of the sensors and connected the white to H, blue and brown to (-) and (+) 18V, and then connected blue to every possible configuration of L and GND. I still have not had luck. Would you recommend changing the flow sensor settings to current output and trying to use the resistor and connect it that way? I called the manufacturer and they said to connect it with "Brown to 18V+, Blue to 18V-, black (or white if it is configured that way) to the DAQ input, and then the blue wire to negative on the DAQ." What does negative on the DAQ correspond to? Whenever I connect blue to 18V- and GND, the other sensors go haywire (and I did unplug all of the other sensors and try this, it still did not work)

[JRys]

Could you test the sensor using a digit voltmeter? Connect the black to the voltmeter red and the blue to the voltmeter black. If there's no output, connect a 500 ohm resistor between black and blue. It should output 2 volts at zero flow. 

[Mackenzie Cox]

If I am not getting an output with my voltmeter, which I am not, do I attached the resistor between the blue on the flow meter and the black of the flow meter? or the black of the voltmeter?

Edited October 11, 2023 by Mackenzie Cox

[JRys]

Please connect the resistor between the blue on the flow meter and the black of the flow meter. Connect the voltmeter to the resistor.  Voltmeter Positive lead -> black, Voltmeter Negative lead -> blue. 

[Mackenzie Cox]

I actually got it all working. Thank you for your help