# 4-20ma three wire transducer connection problem

I am trying to connect a 24 volt 4-20ma 3 wire resistive linear transducer to arduino with 4-20ma to 0-5 volt converter (https://www.amazon.com/Isolation-Current-Transmitter-Converter-Transformer/dp/B07ZCPGDG9)

The converter needs two cables like +,- but transducer has three wires and one of them is signal. i couldn’t figure how to wire them together, please help.

No transducer data sheet? My guess is, and only a guess would be your transducer has a VCC (maybe 24 volts) a signal out 4 ~ 20 mA ans a Ground. Signal and Ground / Signal would go to your converter as Iin and Iout likely Ground I - and Signal I +. Then use the pot adjustments accordingly.

Ron

Since the output is a current, not a voltage, you should run it through a resistor to convert it to a voltage so that the Arduino can measure it. V = I x R. If you do the math you'll see that 220 ohms is a good value. 1% tolerance or better, up to you.

MK1888:
Since the output is a current, not a voltage, you should run it through a resistor to convert it to a voltage so that the Arduino can measure it. V = I x R. If you do the math you'll see that 220 ohms is a good value. 1% tolerance or better, up to you.

That would work fine but they already have a current to voltage converter. I normally use either a 250 or 500 Ohm 1% precision resistor and place a 10K resistor at the analog input for protection. 250 Ohm will give you 1 to 5 volts and 500 Ohms will give you 2 to 10 volts, choose depending on the ADC. There is also 65 Ohms popular when using a 1.3 volt ADC reference. Again, since they already have a I to V converter I left out using a resistor.

Ron

Who has a current to voltage converter? The Arduino?

MK1888:
Who has a current to voltage converter? The Arduino?

No, the thread starter. Not the Arduino.

I am trying to connect a 24 volt 4-20ma 3 wire resistive linear transducer to arduino with 4-20ma to 0-5 volt converter (https://www.amazon.com/Isolation-Current-Transmitter-Converter-Transformer/dp/B07ZCPGDG9)
The converter needs two cables like +,- but transducer has three wires and one of them is signal. i couldn't figure how to wire them together, please help.

The link goes to a transducer designed around 4 - 20 mA = 0 to 5 volts. That's how I read it anyway?

Ron