You want to monitor a powerline's frequency while
logging it waveform, but you can't afford to dedicate a channel for
frequency counter, or you want to have a higher resolution with
frequency readings. Activate the MagicMeter or Instrumentation
Gauge WinDaq addon, and use its frequency reading operator, #freq, and
you will get exactly what you wish for.
Note:
To create a frequency counter, select the Advanced math option
and use the #freq operator. In the following example, frequency
from the first channel in WinDaq is displayed.
You can apply math equation to the operator to generate other
display option. For example, RPM = #freq0*60
Select an appropriate Window size.
The larger the window size, the more accurate of the
frequency reading
The larger the window size, the slower response for a
changing frequency
The internal data buffer of WinDaq limits the maximum window
size
Up to 58 channels enabled in Windaq, windows size 1024 can
be achieved
Up to 29 channels enabled in
Windaq, windows size 2048 can be achieved
Up to 15 channels enabled in
Windaq, windows size 4096 can be achieved
Up to 7 channels enabled in
Windaq, windows size 8192 can be achieved
Up to 3 channels enabled in
Windaq, windows 16384 size can be achieved
Only 1 channel enabled in
Windaq, windows 30000 size can be achieved
Auto tracking
The baseline of the waveform is evaluated dynamically. It is
the center of the min/max of the waveform within the sample
window. For example, if the waveform swings between -5V and
1V, the base line will be established at -2V. Later the
waveform drifts up to swing between 1V and 5V, a new base line
will be established at 3V.
Build-in 1% amplitude hysteresis to suppress error from
noisy signal, meaning a rising signal has to cross -1%
amplitude below the
base line and +1% amplitude above the baseline to be considered as
zero-crossing. On the other hand, a falling signal has to cross
+1% amplitude above the
base line and -1% amplitude below the baseline to be considered as
zero-crossing. Taking the examples above, when the
waveform swings between -5V and 1V, the baseline is at -2V,
and the amplitude is 3V, thus the moment when the waveform
from at least -3V*1%+base, or -2.03V, to cross +3V*1%+base, or -1.97V will
be considered as zero-crossing point. In the next example, with the similar
calculation, the zero-crossing region is between 2.98V and
3.02V.