Post by thread:[PIC:] PIC based Redox measurement

I would like to build a PIC based Redox measurement unit. I could not find any information about the signal conditioning path. I know that AC over DC is a preferred method. What about frequency range, and voltage required. What signal magnitude (uV vs mV) can be expected from the probe? I would appreciate any comments. Janusz -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

hello all, Janusz Mlodzanowski wrote: >I would like to build a PIC based Redox measurement unit. >I could not find any information about the signal conditioning path. >I know that AC over DC is a preferred method. What about frequency >range, and voltage required. >What signal magnitude (uV vs mV) can be expected >from the probe? >I would appreciate any comments. >Janusz i have just developed a measurement system for electro chemical potentials based on a 16F877. redox measurement is basicly dc voltage measurement from -1V to +1V and is accomplished with best choice high impedance opamps (like LMC6082) with an additional overvoltage/burst protection circuit in the first stage followed by the adc of 877. the 16f877 does the main work to compute linearity by means of linaer regression and the display/keypad interface. with an additional Pt100-measurement you can compensate the temperature error. the voltage developped at the electrode pair depends on a variety of parameters like material of the electrodes , the reduction and oxidation participants , the pH-value of solution, the temperature etc. btw: the developed measurement system could also be used as a pH-meter and to measure the conductivity. best regards Dieter Baltruschat -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics