mV measurement
1. The "Settings" switch is set to "Measurement", and the "pH/mV" selection switch is set to "mV";
2. Insert the electrode into the solution to be tested, and after stirring the solution evenly, the electrode potential (mV) value can be read.
3. If the measured signal exceeds the measuring range of the instrument, the display screen will not light up and an overload alarm will be issued.
pH calibration and measurement
Calibration: The instrument should be calibrated before pH measurement. Generally speaking, when the instrument is used continuously, it should be calibrated once a day. The steps are as follows:
a) The "Settings" switch is set to "Measurement", and the "pH/mV" selection switch is set to "pH";
b) Adjust the "temperature" knob so that the white line of the knob points to the corresponding solution temperature value;
c) Turn the "Slope" knob clockwise to the end (100%);
d) Insert the cleaned electrode into a buffer solution with a pH value of 6.86;
e) Adjust the "positioning" knob so that the instrument display reading is consistent with the pH value of the buffer solution at the current temperature;
f) Wash the electrode with distilled water, then insert it into the standard buffer solution with pH value of 4.00 (or pH value of 9.18), and adjust the slope knob to make the instrument display reading consistent with the pH value of the buffer solution at the current temperature;
g) Repeat (e) to (f) until the "positioning" or "slope" adjustment knobs are not adjusted. At this point, the instrument is calibrated. "Position" and "Slope" should not move until the next calibration.
pH measurement: A calibrated instrument can be used to measure pH. The steps are as follows:
a) The "Settings" switch is set to "Measurement", and the "pH/mV" switch is set to "pH";
b) Clean the electrode head with distilled water, and then clean it once with the solution to be measured;
c) Use a thermometer to measure the temperature of the solution to be tested;
d) Adjust the "temperature" knob so that the white line of the knob points to the corresponding solution temperature value;
e) Insert the electrode into the solution to be tested, and after stirring the solution to make the solution uniform, read the pH value of the solution.