OHAUS starter 3100, Инструкция по эксплуатации

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8
3.1.2 Performing 1-point calibration
Calibration: pH electrode need to be calibrated with pH standard buffer solution before a proper
pH measurement. Calibration is to display the right pH value when meter receive 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);
When
STARTER 3100
is in pH measurement mode (see 3.2); place the pH electrode in a
calibration buffer, then:

Press button- Cal ,
“
Cal
1
” displays on the bottom left of the screen and “
Cal
” is blinking.
and appear on the top of the screen, is blinking during calibration.

The meter reaches endpoint according to the endpoint mode , the calibration point pH value
(e.g. 7.00) with the temperature display on the screen.
The 1-point calibration is finished; now we have 3 choices to do next:

Press button- Cal to do the 2-point calibration.

Press button- Read to store the 1-point calibration and exit, the offset and the slope are
shown on the display for 3 seconds then return to the measurement screen.

Press button- Exit to reject the calibration, return to the measurement screen.
Endpoint Mode : We have two endpoint modes - auto endpoint and manual endpoint . By
pressing and holding button- Read , you can switch between the 2 endpoint modes.
o
To manually endpoint a measurement or calibration, you need to press button-
Read : the sample reading freezes, the endpoint stability icon blinks 3 times
and freezes on the display.
o
When in auto endpoint mode, the meter judges if the reading is stable then
endpoint automatically, the reading freezes and blinks 3 times then disappears;
auto endpoint icons
blink 3 times and freeze on the display.
o
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.
3.1.3 Performing 2-point calibration

Perform 1-point calibration as described above.

Rinse the pH electrode with pure water and wipe off with tissue.

Place the electrode in the next calibration buffer and press button- Cal ,
“
Cal
2
” displays on the
bottom left of the screen and
“
Cal
” is blinking. on the top of the screen
and appear,
is blinking during calibration.