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* If the standard solution in the bottle is spilled, replenish the bottle with the phthalate pH standard
solution to protect the glass electrode from becoming dry. Adding distilled water, pure water or tap
water before storing is recommended.
Before measuring
(1) Connect the PHP-31 sensor probe to the main unit.
(2) Press the PWR key. The whole LCD lights up for three seconds to indicate that the unit has been turned on.
When the temperature of the sample liquid is known, disconnect the temperature sensor connecting plug
and press the SKIP key for two seconds or more to enter the manual temperature setting mode. Set the
temperature to the desired reading by u
sing the pH/mV key (↑) or the
key (↓). Press the REC key to
confirm.
(3) Perform the pH calibration after changing the battery or when a very accurate pH
measurement is necessary.
(4) The unit is turned off by the auto power-off function if no key is operated for 20
minutes. Turn off the auto power-off beforehand if measurement is to be done
continuously. Press the PWR key while pressing the CAL key at the same time to
turn on the unit, and then release the PWR key. When the "n" character appears on the display, release
the CAL key. This cancels the auto power-off.
Note: Auto power-off is no longer cancelled once the unit is turned off. Perform the auto power-off canceling
each time as necessary.
Calibration mode
By performing the 3-point calibration, this instrument can accurately measure the pH. Perform the pH
calibration in the following cases:
a) After replacing the sensor probe
b) After replacing the battery
c) When very accurate measurement is necessary
For more accurate measurement, calibration of about once a day is recommended.
For calibrating the SK-620PH, prepare the following items.
pH 4 standard solution (phthalate solution):
pH 4.01 (at 25°C)
pH 7 standard solution (neutral phosphate solution):
pH 6.86 (at 25°C)
pH 10 standard solution (carbonate solution):
pH 10.01 (at 25°C)
Distilled water, pure water or tap water
Four beakers (each beaker to contain one type of standard solution or water (distilled, pure or tap water)
To ensure accuracy, perform calibration at the same temperature as the material to be measured. The pH
standard solution bottle which comes with the instrument can be used as a substitute for a beaker.
How to calibrate the SK-620PH series pH meter
(1) Connect the PHP-31 sensor probe to the main unit.
(2) Press the PWR key to turn on the unit. The unit enters the measurement mode. Remove the glass
electrode protection bottle from the sensor probe.
(3) Thoroughly wash the glass electrode with water (distilled, pure or tap water).
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