JUMO 202710/20, Руководство по эксплуатации

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6 Calibration of the pH combination electrode
6.1 General information regarding calibration
The parameters of pH combination electrodes are subject to fluctuations due
to aging and individual variations. It is therefore advisable to check the calibra-
tion of the combination electrode before taking a measurement. If the devia-
tion is unacceptable, the combination electrode must be recalibrated.
Buffer solutions with an exact pH value are needed for calibration.
The device can be configured for the following buffer series:
• Standard series (4.01 pH, 7.00 pH, and 10.01 pH)
• DIN series (1.68 pH [A], 4.01 pH [C], 6.87 pH [D], 9.18 pH [F],
and 12.45 pH [G])
• or any buffer (neutral buffer within the range 6.5 to 7.5 pH).
6.2 Preparing for calibration
✱
Configure the device for the measurand "pH", see "Parameter "InP":
selection of a measurand", page 35
✱
Select the calibration method (1, 2 or 3 point calibration), see "Parameter
"CAL": selection of the number of calibration points", page 36
✱
Select the buffer series for the calibration, see "Parameter "CAL.P": selec-
tion of the buffer series", page 37
✱
Carefully remove the protective cap (containing 3 mol KCl) from the combi-
nation electrode.
✱
Rinse the combination electrode and the temperature probe (if available)
with de-ionized (distilled) water and dry.
CAUTION!
The operating life of buffer solutions is limited and is significantly shortened
by inadequate cleaning and drying of the combination electrode when
switching between solutions. This can lead to calibration errors!
If possible, use new solutions when calibrating.
Rinse with de-ionized or distilled water!
NOTE!
The automatic temperature compensation when calibrating
Both the signal of the pH combination electrode and the pH buffer are
dependent on temperature. A Pt1000 temperature probe (optional) con-
nected to the manual measuring device automatically compensates for tem-
perature influence.
If a temperature probe is not available, the actual temperature of the respec-
tive buffer should be entered as accurately as possible, see chapter 6.4 "Cal-
ibration without temperature probe", page 25.
The temperature influences of the buffers are also compensated for when
using the standard buffer series or the DIN buffer series.
When using any buffer, the pH values of the buffers must be entered in line
with the current temperature.