I am looking to read a signal from a pressure sensor. It requires a higher voltage 10-36V DC power supply.
I was wondering if it is possible to hook up to the arduino uno to collect data.
I am a novice in this space but was pointed towards using an arduino for this task. I worry that I may fry whichever input I put this into though.
Could the negative side of the power supply connect to the digital pins and the ground to the COM in the 4-20mA diagram?
The simplest way to read a 4-20 mA output with the Arduino Uno is to use a 250 Ohm resistor to convert the current signal into a voltage signal, which you measure using the analogRead function. Calibration is usually required, but roughly speaking, 4 mA produces 1V and 20 mA produces 5V.
Wiring diagram:
To protect the analog input against voltage spike, an additional 10K resistor can be placed between the analog input and the 250 Ohm resistor.
And this is a very good idea, as sooner or later you'll either power down the Arduino with the external supply on, or you'll disconnect the 250 ohm resistor(inadvertently, I hope), and the Arduino will go 'pop'. At that point, you might still have another analog input that works, or not, and you might have an Arduino that works, or not. Better to put in the 10k resistor (in the blue trace @jremington drew).
What is your sensor's EXACT part number? Are you using the 4 ~ 20 output or the voltage output? And which Arduino?
Thank you very much, I was a bit scared to fry something. This worked, now I can actually read my pressure sensor!
I added the 10k resistor as suggested, and tested it out too. It did the trick!
now am doing the 4-20 with Arduino Uno R3. the pressure sensor is Dwyer MSX Magnesense MSX-W12-PA
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