Since 1991, the acid rain observation stations in my country have used the PH-3C PH meter produced by Jiangsu Electric Analytical Instrument Factory to measure the pH value, and the conductivity value has used the DDS-11A conductivity meter produced by Shanghai Leici Analytical Instrument Factory. As time goes by, the performance of this batch of instruments generally declines, frequent failures, and unstable measurement data. The average of three parallel readings and manual temperature correction are used, as well as three-point positioning and slope adjustment. The operating procedures are cumbersome, resulting in deviations in observation data , the reliability of the measurement data is poor.
The updated instruments used the PH-3B PH meter and DDS-307 conductivity meter produced by Shanghai Leici Instrument Factory. These instruments have greatly improved in measurement accuracy, resolution and measurement methods. PH-3B type PH meter is equipped with E-201-C-Q 9 composite electrode, with 3.5 decimal digital tube display, PH measurement range is 0-14PH, accuracy ±0.005PH, resolution 0.001, 0.01, 0.1PH optional , take automatic temperature compensation and two-point calibration, the measurement data shows stability. After the calibration of the instrument for measurement, only one reading is required, no manual temperature correction is required. The operation procedure is simple, convenient and fast, the work efficiency is high, and the observation data is true and reliable.
