Data Scaling

This is a data-processing layer for scaling of input data. This can be applied to any variable (read by Modbus, analog or any sensors). Following are the basic steps to use this feature:

  1. Click on Open DataScale Settings button. It will open table with dummy values.

  1. Click on Read DataScale Settings button. It will update the table with actual DataScaling settings for a given variable (if present).

  1. Update the variable names and scaling. It is mandatory to have Enable Scaling Flag ticked to get a given scaling function enabled.

  1. Click on UpdateDataScale Settings button to update the data scaling features.

Data Scaling Processing

For a given variable, following Data Scale function is applied:

a) The variable is scaled using values provided in the Input Range (Minimum and Maximum) to the Out Range (Minimum and Maximum). b) After the above step, the output values are clipped to be within range of Minimum Cutoff Limit and Maximum Cutoff Limit values.

It is not mandatory that variable should be within Input Range value. Input and Output Range values are used to create the slope and offset (y=mx+c) to derive at output value. Finally, the output values can be clipped using Cutoff Limit values.

Explanation of DataScale function in representative example:

1) analog1_celcius: Input values 0 to 20 (mA) will be scaled to -5 to 55. This example uses an analog temperature. The output values are clipped to -5 to 55. Just in case analog value becomes >20 or <0 due to calibration error, the output will always be in range -5 to 55.

2) analog2_aox: This example represents an air analyzer sensor, in which 4-20mA range represents value of 0 to 600. In case the sensor is OFF (or not working), the input values of 0mA (any value less than 4.0) will first be calculated as a -ve value. But it will be clipped to be in range of 0 to 600 using Cutoff Limits.

3) analog3_freq: This represents an AC drive which gives frequency output in 0-20mA range. However, as it was identified during calibration that actual mA output of AC drive was only 19.8 at full 50Hz frequency, we scale 0-19.8 input to 0-50Hz and apply cutoffs.

4) analog4_humidity: A sample humidity scaling function. In this case, the error cases are identified using out-of-range limits (-1 to 101) to represent error scenarios.

Scaling functions applied to 4 variables (as defined in analog section). Enable Scaling Flag has been ticked to have scaling function enabled.

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