Operating The Instrument; Calibration; Buffer Groups; Selecting A Predefined Buffer Group - Mettler Toledo FiveEasyPlus FEP20 Bedienungsanleitung

5 Operating the instrument
5.1 Calibration
5.1.1 Buffer Groups
The FiveEasyPlus™ pH meter allow you to perform 1, 2, or 3 point calibrations. After selecting your
calibration buffer group from the predefined buffer groups in the meter, the buffers are automatically
recognized and displayed during calibration (auto buffer recognition).
The four predefined groups are:
B1 1.68
B2 2.00
B3 1.68
B4 1.68
Tables (B1...B4) for automatic temperature compensation are programmed in the meter for each buffer
group (see also "Appendix (page 18)").
5.1.2 Selecting a predefined buffer group
1 Press and hold the Mode/Setup key until the setup icon appears on the display and the MTC tem­
perature blinks.
2 Press Read to ignore – the current temperature unit blinks – press Read to ignore again.
When the current buffer group blinks, the buffers belonging to this buffer group appear alter­
nating on the display.
3 Use or to select another buffer group and press Read to confirm your selection.
The meter will exit automatically to the measurement screen.
5.1.3 Performing a 1 or 2-Point Calibration
– Place the electrode in a calibration buffer and press Cal.
The calibration icon and the measurement icon appear on the display.
The meter endpoints according to the preselected endpoint mode after the signal has stabilized or
after pressing Read. The relevant buffer value is displayed and stored; the measurement icon dis­
appears from the display.
To perform a 2-point calibration rinse the electrode with deionized water, place the electrode in the
next calibration buffer and repeat the step above.
1 To finish the calibration and return to the sample measurement, press Read.
The offset value and the slope are then shown on the display for 3 seconds.
2 To reject the calibration, press Exit before the meter returns automatically after 3 seconds to the
measurement screen.
Note
With the 1-point calibration only the offset is adjusted. If the sensor was previously calibrated with
muti-point calibration the previously stored slope will remain. Otherwise theoretical slope (-59.16 mV /
pH) will be used.
5.1.4 Performing a 3-Point Calibration
1 Step 1: Perform the first and second calibration steps as described above in "Performing a 1 or
2-Point Calibration (page 9)".
4.01 7.00
4.01 7.00
4.00 6.86
4.01 6.86
10.01
9.21 11.00
9.18 12.46
9.18

Operating the instrument

(at 25°C)
(at 25°C)
(at 25°C)
(at 25°C)
9