pH-Calibration
The two-point calibration process can be started under menu item
"ph calibration".
¢ LCD display see fig. 20
Calibration can be cancelled at any time using the L and M buttons.
Calibration is used to adjust the unit for the measurement chain
being used. The process determines the zero point and the pH gra-
dient for the measurement chain.
The calibration should be carried out using pH 4 and pH 7 buffer
solution as per DIN 19266.
Other buffer solutions, including those with identical rated values,
may exhibit different temperature characteristics, which will lead
to measurement errors.
• First, immerse the measurement chain and the temperature sen-
sor in the pH 7 buffer solution. The rated value for the required
buffer solution will be displayed, see fig. 20.
• Press the SET button to start the calibration process, see fig. 21
(duration up to 3 min.).
• Remove the measurement chain and the temperature sensor
from the first buffer solution as soon as the rated value for the
second buffer solution appears on display (see Fig. 22). Rinse
both items thoroughly with distilled water and dry using a soft,
lint free paper towel. Do not rub!
• Next, immerse the measurement chain and the temperature
sensor in the pH 4 buffer solution.
• Press the SET button to restart the calibration process, see fig. 23.
The gradient for the measurement chain in % (mV/pH) will be dis-
played at the end of the calibration.
The calibration process was successful if the gradient is between
90%-105%, see fig. 24. The calibration values will be saved auto-
matically.
• Confirm the setting using the SET button
22
If the gradient is outside this range then the calibration values will be
rejected. The measurement chain should be swapped in this case.
PT 1000-Calibration
The ETS-D6 is pre-calibrated without a sensor before shipping.
Sensor tolerances in accordance with DIN IEC 751 Class A are not
taken into account.
The complete measurement chain can be calibrated in order to eli-
minate the effects of the contact resistance at the plug connector
and the sensor tolerances (inclusive of temperature drift).
The calibration process is started using the "PT1000 calibration"
menu.
The following items are required:
- An additional temperature measuring device with an accuracy
of + 0.05 °C
- Two stable, constant temperature sources
(media at different, controlled temperatures)
• Immerse both sensors in the first medium. Wait until the display
on the temperature measurement device has stabilised.
• Enter the measured temperature on the ETS-D6 using the
L and M buttons.
• Confirm the value entered using the SET button, see fig. 25.
• Immerse both sensors in the second medium. Wait until the dis-
play on the temperature measurement device has stabilised.
• Enter the measured temperature on the ETS-D6 using the
L und M buttons.
• Confirm the value entered using the SET button, see fig. 26.
The calibration is now successfully completed, see fig. 27.
012007