Endress+Hauser Viomax CAS51D, Operating Instructions Manual

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Operation Viomax CAS51D
26 Hauser
Device condition and specifications Notes
Is a sufficient length of the cable cores stripped, and is it positioned in the
terminal correctly? Check the fit (by pulling
gently)
Are all the screws terminals properly tightened? Tighten
7 Operation
‣
Verify that a representative measured value is displayed on the transmitter.
‣
For solids that have a tendency to form deposits, ensure that the medium is mixed
sufficiently.
7.1 Calibration
Calibration is performed in the process by comparing the values to an external standard
method, by calibrating with standard solutions or by using a combination of both (addition
of standard).
7.1.1 Factory calibration
Nitrate sensor
The sensor is precalibrated on leaving the factory.
As such, it can be used in a wide range of clear water measurements without the need for
additional calibration.
SAC sensor
The sensor is precalibrated on leaving the factory (calibrated with KHP).
Calibration to the customer process is nevertheless advantageous in the majority of cases.
Reason: Organic compounds other than KHP react differently in the spectrum.
The factory calibration is based on a three-point calibration of. The factory calibration
cannot be deleted and can be retrieved at any time. All other calibrations - performed as
customer calibrations – are referenced to this factory calibration.
7.1.2 Types of calibration
In addition to the uneditable factory calibration, the sensor stores six other data records.
Each calibration data record can have up to five calibration points.
• Single-point calibration
This causes a change in the slope. This type of calibration is used if the measured value
only changes to a limited extent.
• Two-point calibration
This causes a change in the slope and zero point. This type of calibration is used if the
measured value changes to a large extent.
• Multipoint calibration
Calibration at three or more points always causes the measuring curve to be recalculated
(including zero point and slope).
• Temperature adjustment by entering a reference value
If you use one or two medium concentration values for calibration, the factory data record
is recalculated using these measuring points (non-linear function) and saved as the new
data record. The original factory calibration is not lost.