ABB AW400 Series - ORP Calibration: Negative Values; ORP Calibration: Positive Values

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6.1.4.1 "OXIDATION potential with NEGATIVE values" arrangement
P1 will be the value of the oxidant standard solution, and P2 the value of the reducent standard solution. In
case both the standard solution have the same sign, P1 will be the standard solution with the lower value.
Press the MENU key to enter the Instrument Calibration submenu and enter the CALIBRATION menu and
then the channel of the ORP probe. The following display will appear:
X X . X X R X 2 3 . 5 ° C
P 1 : YY.Y
P1 indicates the first point of calibration. XX.XX is not a REAL value, but it shows when stability of measure
has been reached. YY.Y is a value set at the last calibration and can be freely modified according to the
chosen buffer solution. Press ENTER and insert the correct value. Wait 3 minutes after the measure in XX.XX
has stabilised (XX.XX is stable), then press ENTER to save the value (press END if you don’t want to save the
value).
Pass on to the second point (P2, higher value) of calibration pressing the button MENU. Take the sensor out
of the first standard solution rinse it thoroughly with de-mineralised water, dry it and immerse it in the second
standard solution. Stir softly but continuously the probe: in this way a shorter stabilisation time would be
required.
Wait until the measurement is stabilised (no more variations of XXXX shown on the display). If needed,
correct the ORP value pressing the ENTER key and inserting the correct value, according to the second
buffer solution ORP value. If you want to save these values push the ENTER key. If you don't want to save
above mentioned calibration parameters press END. If the ENTER key is pressed new calibration data are
overwritten to previously stored values in not volatile memory.
To start the measure press the END key and the display will show the measured value.
NOTE:
The calibration procedure can be performed also at two values which are outside from the
measuring range selected, depending on the buffer solutions which are available for the
calibration.
6.1.4.2 "OXIDATION potential with POSITIVE values" arrangement
Calibration is similar to the previous one but P1 is the value of the reducent standard solution, and P2 the
value of the oxidant standard solution. In case both the standard solution have the same sign, P1 will be the
standard solution with the lower value.