2-15
IM 701240-01E
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App
Index
Explanation of Functions
Deceleration Prediction and Stop Prediction
The 701280 (FREQ) automatically performs internal computation and displays waveforms
by predicting the deceleration curve and stop point even when the input pulse is suddenly
cut off. This function allows the measurement of waveforms of deceleration behavior that is
close to the actual physical phenomenon in applications in which the deceleration behavior
of an object that have inertia is measured such as in the brake test of automobiles.
Deceleration Prediction
The deceleration curve is computed according to the following equation using the
elapsed time after the pulse input stops (
∆
t).
Frequency (f) = 1/period (
∆
t)
The deceleration prediction starts after a pulse period (T) of the pulse one period
before the pulse input stopped elapses after the pulse input stopped.
Stop Prediction
The function determines the stop point at a constant time after the pulse input stops,
and the frequency is set to 0. The time from the point when the pulse input stops to
the point when the function determines that the object has stopped can be set to
×
1.5,
×
2,
×
3, ... ,
×
9, and
×
10 (10 settings) of the pulse period (T) of the pulse one period
before the pulse input stopped.
f
0
T
T
×
n
n: 1.5 to 10
f = 1/ t
t
Deceleration
prediction
Pulse input stop
Stop prediction
0
Filter
Smoothing Filter (Moving Average)
The frequency module can display waveforms by taking the moving average of the
data in realtime. The order of moving average can be set in terms of time in the range
of 0.1 ms to 1 s (up to 25000
th
order). The order of moving average is equal to the
specified time divided by 40
µ
s.
The smoothing filter has the following characteristics.
• Converts a waveform that changes in steps to a smooth waveform.
• Improves the resolution by reducing the measurement jitter. The resolution improves
especially when measuring high frequencies or when expanding the display using the
offset function. Consequently, highly accurate measurements can be made.
• Can be used on all measurement parameters of the frequency module.
Original
waveform
When using the smoothing filter
Filter order: 400 ms
2.2 Setting the Horizontal and Vertical Axes