Endress+Hauser Viomax CAS51D, Operating Instructions Manual

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Operation Viomax CAS51D
28 Hauser
7.1.5 Nitrate sensor
Processes with nitrate values > 0.1 mg/l
1. Take a sample and determine the nitrate concentration in the laboratory.
2. Calibrate and adjust the sensor with the laboratory value.
Processes with very different nitrate values
1. At time A, take a sample with a high concentration, and measure and calibrate the
sample.
2. At time B - which can be a few days after time A - take a sample with a low
concentration, and measure and calibrate the second value.
Calibration with the addition of standard
If the sludge parameters tend to be constant, you can perform the calibration with a
sample with a low concentration of nitrate and then add standard to the sample.
1. Take a larger sample (bucket) and analyze some of it by colorimetric means.
2. Calibrate the value of the calorimetric measurement in the sensor.
3. Add standard to the sample and determine its laboratory value.
4. Calibrate the laboratory value of the sample with added standard in the sensor.
Avoid incorrect measurements.
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Drinking water may contain higher concentrations of nitrate and is not suitable as a
blank value. Use fully deionized water as a blank value.
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During calibration, make sure the sample is homogeneous.
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When calibrating, start with a low concentration and increase the concentrations
gradually to prevent nitrate carryover.
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Clean and dry the sensor after a calibration. Ensure that there is no medium residue in
the cuvette gap. In this way, you avoid mixing the different samples and changing the
nitrate concentrations.
7.1.6 SAC sensor
General calibration steps
1. Take a sample.
2. Determine the SAC value of the sample in the laboratory.
3. Calibrate and adjust the sensor using the laboratory value.
In the SAC sensor version, the calculated variables COD, TOC, BOD and DOC can also be
output if desired, in addition to the actual measured variable. These variables are based on
the following ratios:
1 mg/l KHP = ~1.176 mg/l COD
1 mg/l KHP = ~0.4705 mg/l TOC
1 mg/l KHP = ~1.176 mg/l BOD
1 mg/l KHP = ~0.4705 mg/l DOC
Use other conversion factors
Sometimes the conversion factors for COD, TOC, BOD or DOC are predetermined by control
bodies. In such instances, these factors can be adjusted as follows:
1. Copy the factory data record to a free data record of your choice in the SAC basic
setting.
A copy is necessary because the factory data record cannot be modified. If you already have
another data record, you can change its factors directly.