Digital evaluation circuit for measuring nitrate concn. in soln. or suspension - uses ion-sensitive electrodes and thermometer probe with A=D converter, micro-controller, EPROM and EEPROM sections

摘要

The output of a sensor (1) corresp. to the temp. and concentration values of the medium is fed in time-share operation via an A/D converter (2) to a microprocessor (3). The microprocessor has a 2kByte EPROM (4) and an EEPROM (5). The appts. may have a keyboard input (6) and an LCD display (8). The EPROM stores the characteristic graphs, the temp. correction as well as the working cycle functions, and the EEPROM stores the upper and lower calibrating points with their temp. ADVANTAGE - Using two-point calibration directly before measurement, eliminates errors to give simple, quick and reliable measurement.