Performing 1-Point Calibration - OHAUS ST300 Instruction Manual

EN-10
5 ° C 1.67
10 ° C 1.67
15 ° C 1.67
20 ° C 1.68
25 ° C 1.68
30 ° C 1.68
35 ° C 1.69
40 ° C 1.69
45 ° C 1.70
50 ° C 1.71
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
Mode.
Auto or Manual End point Mode:
Press and hold
o
When in Manual Mode, to manually reach a pH measurement or calibration value,
o
you need to press button-
sample reading or calibration value freezes,
the display.
When in Auto End Point Mode, the meter determines when the reading is stable
o
then displays and locks the reading or calibration value automatically, the reading
freezes and
the display.
Please note stability criterion: the signal of the sensor input may not change by
o
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.
4.01 7.09
4.00 7.06
4.00 7.04
4.00 7.02
4.01 7.00
4.01 6.99
4.02 6.98
4.03 6.97
4.05 6.97
4.06 6.96
to change the End Point Mode.
blinks 3 times then disappears;
STARTER 300 Portable pH Meter
10.25
10.18
10.12
10.06
10.01
9.97
9.93
9.89
9.86
9.83
to ensure the meter is in Auto End point
when reading is stable and displays
blinks 3 times and freezes on
blinks 3 times and freezes on
: then the