Tuning the sensor value
Sensor readings can be tunned by a linear formula "y = k * x - b"
Example VT407 + HAT-100Q1 / AC current converter:
Metered current for HAT: from 0 to 100A (This means that the range equals 100,
)
k = 100
The output of VT407 is 0-5V (That means that the range is equal to 5)
" " = the value that the sensor shown in WebUI when there's no current. Let's say that
b
b = + 0.021
You should use the following formula for HAT: 100/5*(x-y)
The expression formula would be 20*(x-0.021)
Example: Using fuel tanks.
Each fuel tank has it's own formula for volume vs height. Please see this useful resource for finding out such a formula.
https://www.calculatorsoup.com/calculators/construction/tank.php
In this can, You need to use non-linear formula.
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Vutlan s.r.o. (LLC)
Remote Infrastructure Monitoring and Control
Example: Why do we need to use Hysteresis
Let’s say that we have a temperature sensor. Let’s say that we have set up threshold values.
We have set the value 25.5 °C to be a threshold value between Normal/Alarm states.
If the temperature drops just below 25.5 °C You will have a “Normal” state.
If the temperature goes just above 25.5 °C You will have a “Warning” state.
Sometimes the temperature may stay at 25.5 °C and jump up and down by 0.1-0.3 °C. In this case, You will get too
many notifications that the sensor is showing Warning or Normal state.
In this case, we need to use a Hysteresis.
If the type “time” is chosen, the system will wait for a specified time before the State of the sensor is declared.
If type “value” is used, unless the temperature drops by a larger amount than specified, the sensor state will not be
declared.
