MemoTrans
25
10 Calibration
10.1 pH Sensor
1-point calibration
The measured value is adjusted with a known reference value (buffer solution or known
medium). The zero offset is stored in the sensor.
2-point calibration
Calibration adjustment of zero point and slope of the sensor with 2 buffers.
Sampling
The measured value is adjusted with a known reference value (buffer solution or known
medium). The zero offset is stored in the sensor.
10.2 ORP Sensor
1-point calibration
Calibration (mV): The measured value is adjusted with a known reference value (buffer
solution or known medium). The zero offset is stored in the sensor.
ORP % assignment
The measured value in mV is converted to a % concentration using a conversion table.
10.3 Combo Sensor (pH/ORP)
pH
1-point calibration
The measured value is adjusted with a known reference value (buffer solution or known
medium). The zero offset is stored in the sensor.
2-point calibration
Calibration adjustment of zero point and slope of the sensor with 2 buffers.
Sampling
The measured value is adjusted with a known reference value (buffer solution or known
medium). The zero offset is stored in the sensor.
ORP
1-point calibration (mV)
1-point calibration is used if only the deviation from a reference value is to be detected
rather than an absolute value.
ORP % assignment
The measured value in mV is converted to a % concentration using a conversion table.
10.4 Conductivity Sensor
Cell constant
The electrical resistance or its reciprocal, the conductance G, is calculated according to
Ohm’s law. Using the cell constant k determined by the sensor geometry, the specific
conductivity κ is determined from the conductance.
10.5 Oxygen Sensor
Air 100 % rH
The sensor signal in the presence of oxygen is determined by calibrating the sensor in
air saturated with water vapor. For this model to work properly, the sensor to be cali-
brated must be near a water surface or, for example, in the gas-filled space of a vessel
partially filled with water.
H
2
O air saturated
The sensor signal in the presence of oxygen is determined by calibrating the sensor in
water saturated with air.
Air variable
This calibration model is for all applications in which air pressure and air humidity in
the environment of the sensor do not correspond to the aforementioned atmospheric
standard values, but are nevertheless known. Both values can be specified here.
Sampling
The measured value is adjusted with a known reference value.
