Knick Stratos Pro A4..MSPH series, Instruction Manual

Page: 86 / 148

86
Zero Adjustment (ISFET)
This adjustment allows the use of ISFET sensors with diff ering nominal
zero (pH only). The function is available when Sensor selection =
MEMOSENS has been set during confi guration. Zero adjustment is
disabled for any other sensors.
The adjustment is made using a zero buff er (pH 7.00).
Permitted range for buff er value: pH 6.5 ... 7.5.
Temperature-corrected input. Maximum zero off set: ± 200 mV.
Display Action Remark
Select Calibration.
Press
enter
to proceed.
Ready for calibration.
Hourglass blinks.
Display (3 sec)
Now the device is in
HOLD mode.
Immerse sensor in a pH
7.00 buff er. Enter the
temperature-corrected
pH value in the range
6.50 to 7.50 using the
arrow keys (see buff er
table).
Confi rm with
enter.
If the zero off set of
the sensor is too
large (> ± 200 mV),
a CAL ERR error
message is gener-
ated. In that case the
electrode cannot be
calibrated.
Stability check.
The measured value
[mV] is displayed.
The “hourglass” icon is
blinking.
Please note:
Stability check can
be stopped (by
pressing
enter
).
However, this re-
duces calibration
accuracy.
Zero adjustment