9-20
IM 701830-01E
Waveforms/variables that can be computed
CH waveforms (C1 to C16), Math waveform (M1 to M7), variable T (The total number of data
points in the time direction is defined to be T. It is displayed as a rising line on the screen.)
However, computation cannot be performed on channels that have logic input modules
installed.
Combinations that are not allowed in computing equations
• An equation of a large number cannot be placed in an equation of a smaller number.
(For example, you cannot specify M2 when you are entering the equation for M1.)
• Computation containing only constants (K1 to K5) are not allowed.
• Only one operator can be used in a FFT equation.
• Only one operator can be used in an equation when making a pulse width computation.
• Only two operators can be used in an equation for FILT1 and FILT2.
Setting Range (Start Point/End Point)
The DL716 can perform computation on up to 100 kW of data. However, when there are only
two or less equations, the computation can be performed on up to 400 kW of data.
Digital Filter
There are 3 types of filters as follows.
Type
Band
Gaussian
Low Pass
Sharp
Low Pass/High Pass/Band Pass
IIR (Butterworth)
Low Pass/High Pass/Band Pass
Setting range of the cutoff frequency:2.0% to 30.0% of the sampling rate
(in 0.2% steps)
Averaging the computed data/computing the peak
Averaging and peak computation can be performed on the computed data. Four types of
operations are available: linear/exponential/cycle/peak.
For linear averaging, set the average count (acquisition count, 2 to 128, in 2
n
steps). For
exponential averaging, set the attenuation constant (2 to 256, in 2
n
steps).
Make sure to specify which waveform, time axis waveform or frequency waveform, to take the
average. Specifying a wrong waveform will give a meaningless result.
For cycle averaging, set the number of data points of one cycle (Cycle Count) in the range, 10 to
1000. This number is applied to the data from the start to the end of the computed data, but the
remaining data that cannot be divided by the “Cycle Count” are ignored.
For peak computation, the maximum value at each point of the computed data are determined
and the waveform is displayed. For each computation, the new computed value is compared
with the past value and the larger value is kept.
Example of cycle averaging
When the record length is 10 k, the “Cycle Count” is 720, the start point of computation is
–5.000 div, and the end point is +5.000 div.
10 k/720 = 13.88 13 cycles will be averaged.
13
×
720 = 9360 Data between the start point to the 9360th point will be cycle averaged.
• Precautions on averaging computed data/peak computation
The auto scaling is defined for the 1st computed waveform.
If you would like to obtain a computed waveform whose amplitude varies significantly after
averaging (e.g. Coherent function ), please set the manual scaling.
For details on the manual scaling, refer to “9.9 Manual Scaling.”
Constants
Constants can be set in the range from -1.0000E+30 to 1.0000E+30.
Computing range and display units
For details regarding the computing range and the display units of the math waveform, refer to
Section 9.3 “Setting Computing Range and Display Units, and Recomputing.”
Threshold level of binary computation
With binary computation, the specified waveform (CH1 to CH16, Math1 to Math8) is converted
to a digital waveform of “0” and “1” with respect to the threshold level (Upper, Lower).
1
0
Upper
Lower
9.10 Executing User Defined Computation (Optional)
