Activity › Forums › Questions & Troubleshooting › 24V 4-20mA industrial temp sensor, how to connect/read? › Reply To: 24V 4-20mA industrial temp sensor, how to connect/read?
MemberApril 4, 2021 at 4:00 pm
You need to give the sensor “space to breath” (=enough voltage left), otherwise it just won’t work.
If you take this setup (from the product page):
and add the 500 Ohm resistor across the +/- of the instrument shown in the picture, which would then be your Controllino, we can conclude:
- 0,020 A * 500 Ohm = 10V
- 0,004 A * 500 Ohm = 2V
- 24V – 10V = 14V > 8V ! (24V power supply assumed)
And BTW (see datasheet):
Max. Loop Impedance
900 Ω (4-20 mA output)
Put aside your Controllino, only leave the resistor, take a digital multimeter and verify your setup first. When you know what voltages are to be measured, verifying what you measure with the ADC is much easier.
- This reply was modified 1 month ago by Friedl. Reason: Stray DIV tags from the editor again. (PLEASE FIX THIS)