How o measure 4-20 mA Current

I need to measure 4-20mA current output from some sensors. How can i do that ? Currently i use resistive drop to get the analog voltage and provide that to ADC of the controller. Are their any current input ADC ?

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kulky64 over 9 years ago +2

That's basically how you do it. You can check various manufacturers reference designs, for example: Analog Devices: http://www.analog.com/en/design-center/reference-designs/hardware-reference-design/circuits…
uscdadnyc over 9 years ago in reply to oksbwn +2

Is the situation: (a) Measuring DC Current (at Currents mentioned) AS you would using a (temporary) Test Instrument? OR (b) Circuitry that you would build that attaches to the circuitry that you want to…
Robert Peter Oakes over 9 years ago +2

4-20mA is a nice standard for instrumentation measurement and is used in industry extensively. the nice thing about it is it has automatic fault detections as zero = 4mA, any less than 4 means an error…

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kulky64 over 9 years ago

That's basically how you do it. You can check various manufacturers reference designs, for example:

Analog Devices:
http://www.analog.com/en/design-center/reference-designs/hardware-reference-design/circuits-from-the-lab/cn0336.html#rd-overview
http://www.analog.com/en/design-center/evaluation-hardware-and-software/cu_eb_plc_demo_system.html

Texas Instruments:
Single Supply Analog Input Module Reference Design with 16-Bit, 8-Channel ADC for PLC - TIPD166 - TI Tool Folder
Analog Input Module for Industrial Outputs and Temperature Sensors Reference Design - TIPD164 - TI Tool Folder

Maxim:
https://www.maximintegrated.com/en/products/interface/current-loop-products-4-20ma.html
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oksbwn over 9 years ago in reply to kulky64

Thanks..
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uscdadnyc over 9 years ago in reply to oksbwn

Is the situation: (a) Measuring DC Current (at Currents mentioned) AS you would using a (temporary) Test Instrument? OR (b) Circuitry that you would build that attaches to the circuitry that you want to monitor? IF (b) then the previously post Comments will do.
However if the situation is (a) then consider a "Portapow Premium USB+DC Power Monitor (portapow.co.uk). I have one and it works great. Remember this is DC. The documentation is lousy, but I drew-up several diagrams that explains the various connections. Will try to post them here BUT I haven't
gotten a Win10 Driver for the Scanner Portion of my Samsung SCX-4016scx MFP. WRT that I am attempting a "virtual" WinXP w/i my Win10 PC. But that is Tangential to this discussion.
USCDADNYC (NY NY USA)
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uscdadnyc over 9 years ago in reply to oksbwn

Is the situation: (a) Measuring DC Current (at Currents mentioned) AS you would using a (temporary) Test Instrument? OR (b) Circuitry that you would build that attaches to the circuitry that you want to monitor? IF (b) then the previously post Comments will do.
However if the situation is (a) then consider a "Portapow Premium USB+DC Power Monitor (portapow.co.uk). I have one and it works great. Remember this is DC. The documentation is lousy, but I drew-up several diagrams that explains the various connections. Will try to post them here BUT I haven't
gotten a Win10 Driver for the Scanner Portion of my Samsung SCX-4016scx MFP. WRT that I am attempting a "virtual" WinXP w/i my Win10 PC. But that is Tangential to this discussion.
USCDADNYC (NY NY USA)
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