Lenze PLC Designer PLC Designer (R2-x) - Manual (Page 666)

L-force | PLC Designer
PLC Designer Libraries
664 DMS 3.2 EN 02/2011 TD29

Application example:
A temperature sensor provides Volt-values (input IN). These are to be converted to
temperature values in degree centigrade (output OUT). The input(Volt) values range is
defined by the limits IN_MIN=0 and IN_MAX=10. The output(degree centigrade) value
range is defined by the limits OUT_MIN=-20 and OUT_MAX=40.
Thus for an input of 5 Volt a temperature of 10 degree centigrade will result.
STATISTICS_INT
Provided by util.lib.
This function block calculates some standard statistical values:
The input IN is of the type INT. All values are initialised anew when the BOOLean input
RESET is TRUE.
The output MN contains the minimum, MX of the maximum value from IN. AVG
describes the average, that is the expected value of IN. All three outputs are of the
type INT.
Block in FBD:
STATISTICS_REAL
Provided by util.lib.
This function block corresponds to STATISTICS_INT, except that the input IN is of the
type REAL like the outputs MN, MX, AVG.
VARIANCE
Provided by util.lib.
VARIANCE calculates the variance of the entered values.
The input IN is of the type REAL, RESET is of the type BOOL and the output OUT is
again of the type REAL.
This block calculates the variance of the inputted values. VARIANCE can be reset with
RESET=TRUE.
The standard deviation can easily be calculated as the square root of the VARIANCE.