2 example with bin averaging – Campbell Scientific CR10X Measurement and Control System User Manual
Page 126
SECTION 8. PROCESSING AND PROGRAM CONTROL EXAMPLES
8-18
02:
Z=F (P30)
1:
0
F
2:
0
Exponent of 10
3:
1025
Z Loc [ _________ ]
03:
Z=F (P30)
1:
0
F
2:
0
Exponent of 10
3:
1026
Z Loc [ _________ ]
04:
Beginning of Loop (P87)
1:
0
Delay
2:
1024
Loop Count
05:
Z=SIN(X) (P48)
1:
1025
X Loc [ _________ ]
2:
1027
Z Loc [ _________ ]
06:
Z=SIN(X) (P48)
1:
1026
X Loc [ _________ ]
2:
1028
Z Loc [ _________ ]
07:
Z=X*F (P37)
1:
1028
X Loc [ _________ ]
2:
2
F
3:
1028
Z Loc [ _________ ]
08:
Z=X+Y (P33)
1:
1027
X Loc [ _________ ]
2:
1028
Y Loc [ _________ ]
3:
1--
Z Loc [ #1 ]
09:
Z=X+F (P34)
1:
1025
X Loc [ _________ ]
2:
45
F
3:
1025
Z Loc [ _________ ]
10:
Z=X+F (P34)
1:
1026
X Loc [ _________ ]
2:
9
F
3:
1026
Z Loc [ _________ ]
11:
End (P95)
;The FFT is now computed and the power
;spectra results sent to Final Storage.
12:
FFT (P60)
1:
10
Log (base 2) of Samples
2:
1
Power Spectra/Taper
3:
0
Log (base 2) of Bins
4:
1
First Sample Loc [ #1 ]
5:
1
Mult
13:
Beginning of Loop (P87)
1:
0
Delay
2:
512
Loop Count
14:
Do (P86)
1:
10
Set Output Flag High
15:
Resolution (P78)
1:
1
high resolution
16:
Sample (P70)
1:
1
Reps
2:
1--
Loc [ #1 ]
17:
End (P95)
18:
Do (P86)
1:
11
Set Flag 1 High
*Table 2 Program
02:
0.0000
Execution Interval (seconds)
*Table 3 Subroutines
End Program
*
A
Mode 10 Memory Allocation
01: 1030
Input Locations
02:
260
Intermediate Locations
8.11.2 EXAMPLE WITH BIN AVERAGING
The CR10X was used to generate data
simulating wave data from an ocean buoy with
four superimposed sine wave signals, 0.1,
0.125, 0.14, and 0.2 Hz. The 2048 generated
samples simulate a sampling rate of 0.5 Hz or a
2.0 second scan rate. Figure 8.11-3 shows a
plot of part of the simulated signal. A FFT with
8 bin averaging was performed on the data. A
multiplier of 0.1 was used to keep the FFT
results smaller than the +6999 upper limit of low
resolution Final Storage. The results of the FFT
are shown Table 8.11-4 and are illustrated in
Figure 8.11-4.
In the example program, a multiplier of 0.1 is
used in the FFT Instruction. By reducing the
FFT results by a factor of 10, the Low
Resolution output format can be used, thus
maximizing the Final Storage capacity. A Low
Resolution data point requires 2 bytes of Final
Storage memory, while a High Resolution data
point requires 4 bytes. When memory is a
limiting factor, the data should be scaled to be
less than 6999, so the Low Resolution format
can be used.