Solution for measuring 4-20mA current non-invasively

[Maihach]

I have a development project to monitor some information in an industrial environment in which sensors are built into the board. But I will need to add a modification that allows non-invasive readings of sensors already installed in companies that follow the 4 to 20ma reading standard. I thought about using the hall effect sensor, but as I haven't worked with this technology yet I still have doubts as to whether I would be able to take accurate readings within this current range. It would also be possible to use current sensors with Rsense, but it would be invasive. Could you help me choose a sensor for this application?

[Peter BENSCH]

As far as I know, without interrupting the 4-20mA loop and looping in a corresponding node or measuring unit, you have no real chance of measuring the current and sniffing the information from it.

Regards
/Peter

[Maihach]

Ok, and using a sensor with Rsense, which would be the most suitable for this application, considering the smallest Rsense possible?

[Peter BENSCH]

Well, this depends on your circuit for processing the voltage drop and also on the further processing of the processed signal. With very small shunts, you would have to amplify the voltage drop by a large factor, which reduces accuracy and immunity to interference. A typical value could be 160 ohms.

Ultimately, you have to realise this according to your requirements.

Hope that helps?

Regards
/Peter