L-force | plc designer – Lenze PLC Designer PLC Designer (R2-x) User Manual

Page 671

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L-force | PLC Designer

PLC Designer Libraries



DMS 3.2 EN 02/2011 TD29

669

When ENABLE is reset to FALSE, output OUT will not be changed, i.e. no further pulse
will be generated. If you explicitly also want to get OUT FALSE when ENABLE is reset to
FALSE, you might use "OUT AND ENABLE" (i.e. adding an AND box with parameter
ENABLE) at the output.

Example in CFC:

FREQ_MEASURE

Provided by util.lib.

This function block measures the (average) frequency (Hz) of a boolean input signal.
You can specify over how many periods it should be averaged. A period is the time

between two rising edges of the input signal.

Input variables:

Variable

Data type

Description

IN BOOL

Input

signal

PERIODS

INT

Number of periods, i.e. the time intervals between the rising edges, over
which the average frequency of the input signal should be calculated.
Possible values: 1 to 10

RESET

BOOL

Reset of all parameters to 0

Output variables:

Variable

Data type

Description

OUT

REAL

resulting frequency in [Hz]

VALID

BOOL

FALSE until the first measure has been finished, or if the period > 3*OUT
(indicating something wrong with the inputs)

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