EN-10
STARTER
300 Portable
pH
Meter
pH electrodes need to be calibrated with pH standard buffer solution before a proper pH
measurement can be made. Calibration is to display the correct pH value when meter receives
the mV value signal from the pH electrode.
Slope: the linear coefficient between mV and pH according to theoretical value (e.g. -
59.16mV/pH @ 25°C which means 100% slope);
Offset: the mV value when pH value is 7.00. (Theoretical value is 0 mV);
4.1.2 Performing
1-point
calibration
When performing calibration, Ohaus recommends using Auto End Point Mode. After powering
the meter on, be sure the top of the screen shows
to ensure the meter is in Auto End point
Mode.
Auto or Manual End point Mode:
o
Press and hold
to change the End Point Mode.
o
When in Manual Mode, to manually reach a pH measurement or calibration value,
you need to press button-
when reading is stable and displays
: then the
sample reading or calibration value freezes,
blinks 3 times and freezes on
the display.
o
When in Auto End Point Mode, the meter determines when the reading is stable
then displays and locks the reading or calibration value automatically, the reading
freezes and blinks 3 times then disappears;
blinks 3 times and freezes on
the display.
o
Please note stability criterion: the signal of the sensor input may not change by
more than 0.1mV in 6 seconds.
Note: With the 1-point calibration only the offset is adjusted. If the sensor was previously
calibrated with multi-point calibration the previously stored slope will remain. Otherwise theoretical
100% slope (-59.16 mV / pH) will be used.
5 °C
1.67
4.01
7.09
10.25
10 °C
1.67
4.00
7.06
10.18
15 °C
1.67
4.00
7.04
10.12
20 °C
1.68
4.00
7.02
10.06
25 °C
1.68
4.01
7.00
10.01
30 °C
1.68
4.01
6.99
9.97
35 °C
1.69
4.02
6.98
9.93
40 °C
1.69
4.03
6.97
9.89
45 °C
1.70
4.05
6.97
9.86
50 °C
1.71
4.06
6.96
9.83
www.calcert.com
1.888.610.7664
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