100BBasic instructions
7.7 Convert
S7-1200 Programmable controller
208
System Manual, 11/2011, A5E02486680-05
Example (LAD): normalizing and scaling an analog input value
An analog input from an analog signal module or signal board using input in current is in the
range 0 to 27648 for valid values. Suppose an analog input represents a temperature where
the 0 value of the analog input represents -30.0 degrees C and 27648 represents 70.0
degrees C.
To transform the analog value to the corresponding engineering units, normalize the input to
a value between 0.0 and 1.0, and then scale it between -30.0 and 70.0. The resulting value
is the temperature represented by the analog input in degrees C:
Note that if the analog input was from an analog signal module or signal board using voltage,
the MIN value for the NORM_X instruction would be -27648 instead of 0.
Example (LAD): normalizing and scaling an analog output value
An analog output to be set in an analog signal module or signal board using output in current
must be in the range 0 to 27648 for valid values. Suppose an analog output represents a
temperature setting where the 0 value of the analog input represents -30.0 degrees C and
27648 represents 70.0 degrees C. To convert a temperature value in memory that is
between -30.0 and 70.0 to a value for the analog output in the range 0 to 27648, you must
normalize the value in engineering units to a value between 0.0 and 1.0, and then scale it to
the range of the analog output, 0 to 27648:
Note that if the analog output was for an analog signal module or signal board using voltage,
the MIN value for the SCALE_X instruction would be -27648 instead of 0.
Additional information on analog input representations (Page 708) and analog output
representations (Page 708) in both voltage and current can be found in the Technical
Specifications.
