Reading a vessel capacity from a 4-20ma sender

[avz]

Hi
I would like to ask for your advise. I have a vessel of a capacity of 15000lit. I want to display the amount of the liquid inside on a display. I was told by Sick sensors that they have a sensor that can do that and it provides a 4-20ma output. how can I combine it with a display and other device, if needed in order to get a visual reading?
Thanks.

 

[MikeMl]

Convert 4 to 20mA to a voltage like 0 to 1V. There have been lots of previous threads about how to do this on these forums. Use the search function to find them.

 

[KeepItSimpleStupid]

Process Meters can usually read 4-20 mA signals and scale them to Engineering Units. The 4mA is such that the sensor gets power and the reading is scaled so that 4 mA is the minimum of the sensor and 20 mA is the maximum.

See https://www.omega.com/toc_asp/subsectionSC.asp?subsection=D01&book=vhpc for some examples.

 

[MikeMl]

Here is a simple opamp circuit that converts 4...20mA to 0V...1.5V. Reason I picked 1.5V full scale is because you can buy inexpensive digital multimeters that display 1.999V full scale, so 1.500V would be 15000 liters. You will need a low voltage opamp whose common-mode range includes ground and whose output pulls to very near ground, plus a few 1% resistors. The 5V supply should be stable to a few mV.

 

[avz]

Thanks for the circuit, I'll try it. if I'm not wrong, I can buy a digital panel voltmeter module with an 1.999v fsd. could you recommend which ic to use?

 

[MikeMl]

For breadboarding, I would use a LM358 because I have lots, and it will work well enough. There are hundreds of better CMOS rail-to-rail in-out opamps available today.