Metrohm 827 pH lab Manual de usuario descargar pdf (Pagina 41)

6 Methods / Parameters

826/827 pH meter, Instructions for Use 33

6.1.4 pH calibration data

The current pH calibration data can be called up at any time under pa-

ram/cal.data.

If no calibration has yet been carried out then only the theoretical cali-

bration data slope = 100.00 % and pH(0) = 7.000 will be shown and

taken into account for the measurement.

param

├ cal.data

: ├ slope

├ pH(0)

├ variance

├ temperature

├ temp.sensor

├ cal.date

├ cal.time

├ cal.interval

├ buff.type

└

no.of buffers

slope

The slope of the linear calibration curve obtained during the calibration

will be shown here as a percentage. This is a relative quantity which is

based on the temperature-specific value of the Nernst constant (e. g.

59.16 mV at 25 °C). Due to the fact that only pH(0) can be calculated af-

ter a single buffer calibration, the slope is set to 100 %.

This value can be altered manually for test purposes.

pH(0)

This is the second characteristic quantity of the calibration curve. pH(0)

is the pH value at 0 mV. It can also be altered manually for test purpos-

es.

Note!

The manual alteration of either slope or pH(0) is documented by de-

leting the remaining calibration data.

variance

For the calibration with 3 buffers the calibration function will be calcu-

lated as a compensation curve according to the principle of the smal-

lest mean-square error (linear regression). The resulting variance will be

given here.

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Metrohm 827 pH lab Manual de usuario Pagina 41