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Scaling and Calibration
General
Scaling and calibration is a way to change the sensor output from the measured value to another value.
Scaling
Scaling will multiply - or divide - any measured value by a fixed value. Use calibration if you want to change the
output from one measuring unit to another, for example from bar to meter water column.
Calibration
Calibration will add a fixed amount to - or subtract a fixed amount from - any measured value. Use scaling to
correct errors if the input signal has a constant positive or negative offset
When to use it?
You will use scaling and calibration when you want to:
Get the level measurement in other units than Bar
Get a temperature measurement i degrees Fahrenheit
If you want to know the Depth to water instead of the level above the pressure transmitters measuring cell.
How does it work?
The output value from the sensor is applied to a mathematical function. Two different functions are used, one for
sensors on an Instrument Net interface and one for sensors on an analog input.
Instrument Net interface:
Output value (Scale 100% Calibration 100% Sensor value) (Scale 0% Calibration 0%)
Analog interface:
Output value (Scale 2,5V Calibration 2,5V) (2,5V Sensor value) (Scale 0V Calibration 0V)
Why two sets of variables?
Two sets of variables are used, Scaling and Calibration. They both perform the same function, but MJK
Automation ApS recommends that you use them for different purposes. You can combine the values for scaling
and calibration into one, but it will be difficult to 'decipher' the function at a later date.
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USERS MANUAL
CHATTER™ DATA LOGGER
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