User Calibration - wtw NiCaVis 705 IQ TS Operating Manual

Measurement / Operation
Calibration points
and value pairs
Selection of
calibration points
Storage location of
user calibration data
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4.3.2 User calibration

The adjustment is carried out at one or two points within the measuring range.
A value pair is determined at each point. Each value pair consists of the raw
value of the NiCaVis 705 IQ TS sensor and the corresponding reference value.
Each value pair has to be determined at the same time and place as the test
sample as possible. At the time of the calibration, the test sample should be in
a condition that is typical of the application.
If the required accuracy is low, the default setting of the first value pair can be
adopted unchanged. The first value pair is equivalent to the zero point in this
case. The second value pair should be close to the working point of the applica-
tion. This method results in a single-point calibration.
If the application has to cover a wide value range with high measuring accuracy,
both value pairs should be used for calibration. When doing so, the calibration
value pairs should be determined and input at the limits of the application range
as possible.
You obtain samples of different concentrations e. g. by taking two samples
during clearly different conditions of the plant (dry period and rain period).
The measurement results will be ever more accurate the closer the
composition of the test sample corresponds to the status at the time
of the calibration. If there is a fundamental change of the character-
istics of the sample, a new calibration may be necessary.
The calibration data of the user calibration are stored in the IQ S
controller. They are loaded into the sensor during operation and automatically
assigned to the replacement sensor if the sensor is exchanged.
NiCaVis 705 IQ TS
N
ENSOR ET
ba77189e01 05/2017