6.7 Frequency measurement
6.7.1 Overview
In this operating mode the CPU counts the incoming pulses during a specified integration
time and outputs them as frequency value. You can set a value for the integration time
between 10ms and 10000ms, in steps of 1 ms. You can set the integration time in the
parameter assignment screen forms or you can edit them in the job interface of the SFB
FREQUENC (SFB 48).
1
Integration time
2
Count pulse
3
Internal gate (SW gate)
4
Start of frequency measurement
5
Stop of frequency measurement
The measurement is carried out during the integration time and is updated after the inte-
gration time has expired If the period of the measured frequency exceeds the assigned
integration time, this means there was no rising edge during the measurement, a value of
0 is returned. The calculated frequency value is supplied in "mHz" units. You can read out
this value with the SFB parameter
MEAS_VAL
. The number of activated channels does
not influence the max. frequency, which is defined in the technical data.
1
Integration time
2
Count pulse
3
Internal gate (SW gate)
4
Calculated frequency
During frequency measurement the count function at the same channel is
deactivated.
6.7.2 Inputs for the frequency measurement
For frequency measurement, connect your signal to be measured at input B.
n
Channel 0: Pin 3
n
Channel 1: Pin 6
n
Channel 2: Pin 9
Measuring procedure
VIPA System 300S
+
Deployment I/O periphery
Frequency measurement > Inputs for the frequency measurement
HB140 | CPU-SC | 313-5BF23 | en | 19-01
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