Analog circuit design to measure pH value from sensor.

[veerubiji]

Hi,

I would like to design analog circuit that will detect signal from pH electrode senor and sent it to micro controller.

I need analog circuit which process sensor electrode signal into ADC, from ADC to micro controller.

I am thinking about Instrumentation amplifier to get low voltage dc signal from sensor electrodes. I am confusing with the circuit between instrumentation amplifier and ADC.

I am using pH sensor from Pfaudler. Have a look into the sensor **broken link removed**

Thanks.

 

[chuckey]

That link tells you every thing but the things you need to know. Normally PH probes have to operate into an impedance of greater then 500 M ohms and only provide a few mV output. So you need an input amp with an extremely high input impedance which should be protected against static followed by a gain of 1000 or more before your metering circuits.
Frank

 

[ctzof]

I once designed a similar circuit as an interface for an Arduino microcontroller. I follow this great tutorial https://www.sparkyswidgets.com/portfolio-item/ph-probe-interface/ which is more or less what you want. With the proper calibration it worked for me. The circuit is very simple and can be build in a breadboard.

 

[darla1]

hi veeru

you need make the circhuit with opamp to measure the PH output along with voltage offeset

thanks