4-20ma Transmitter with power supply

I’m trying to use the 4-20ma sensor and I’m measure it with the multimeter and the milliamps are jumping around, and not climbing steadily like the one without the power supply.
I’m using the same Arduino sketch. Any ideas on why this is happening?

I have posted this before with no reply.

can you share the product SKU you are using ?


I work in an industry that uses 4-20mA sensors all the time. It is important that a 4-20mA signal be run through a shielded cable so external noise does not interfere. One very important thing to always remember about shielded cable. THE SHIELD IS ONLY GROUNDED AT ONE END. Depending on where the sensor is located and how the signal gets back to the arduino makes the difference in what type wire or cable to use. A sensor located 5 feet away and the sensor is connected with any wire and there is nothing else around it should work fine without shielded cable. If the sensor is located 50 feet away and the connection wire is run through conduit with unshielded cable, you will pick up noise. Noise will make the signal jump around.