CTEK Automation Control Application APN007 - Manual (Page 37)

Application Note – Automation Control Application
APN007 25 July, 2014
32
Figure 31 - Standard Conversion Formula
The standard conversion formula shown above reads the sensors input value and subtracts from
it the minimum range value assigned to the sensor. It then divides the resulting value by the value
of (Max - Min Range). The resulting number is then multiplied by the value of (Max - Min Units)
and also by the correction value assigned. Lastly the value of Minimum Units is added to the
result of all of the preceding operations. This final value will be displayed in the Value field of the
Input screen and on the control panel. As a practical example assume that a 0 - 10 amp current
sensor is installed and when calibrated it has a range of 7 - 4090. The following configuration
would be made on that sensor's Input settings.
Min Range - 7
Max Range - 4090
Min Units 0.00
Max Units - 10.0
Correction Factor 1.0
Unit of Measure - Amps
Sensor value (when read) = 2037
The standard conversion formula would do the following:
Read the sensor (2037) and subtract from it the Min Range (7) resulting in 2030
Divide the result by the value of (Max Range - Min Range) resulting in 0.4972
Multiply by Max Units - Min Units (10 - 0.0) resulting in 4.972
Multiply by correction factor (1.0) resulting in 4.972
Add the value of Min Units (0.00) resulting in 4.972
The Unit of measure (Amps) would then be appended to the calculated value resulting in a
display of 4.97 Amps on the Input screen and the Control Panel.