6. Function blocks
6.1 Manufacturer function blocks
Description Note
(Bit)
OF Overflow
1: if QV ≥ SH
FB Fall Below
1: if QV ≤ SL
ZE Zero
1: if QV = 0
(DWord)
QV QV outputs the number of pulses detected per
measuring interval
The function block operates in the
integer value range from 0…50 000.
QF QF outputs the measured frequency*10. The function block operates in the
integer value range from 4…50 000.
The following formula applies: 10 000 = 1
kHz.
The measurable frequency range is
0.4…5000 Hz.
Assigning operands
You can assign the following operands to the function block outputs that are numeric
outputs:
Assigning operands Outputs
Constant x
Markers: MB, MD, MW x
Analog inputs IA x
Analog output QA x
Numeric output from another QV FB x
You can assign the following operands to the function block outputs that are bit outputs:
Assigning operands Bit outputs
Constant 0, constant 1 x
M – Markers x
SN - Output bit via NET (send) x
N - Network marker bit x
nN - NET station n marker x
LE - Output backlight x
Q - Bit output from another FB x
Example with CF01 with 50 Hz at the input
There is a square wave signal with a frequency of 50 Hz at device input I01. Outputs QV
and QF of function block CF01 will have the following values depending on the chosen
measuring interval:
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