1
2
3
APPEN-
DIX
6
7
8
Appendix 3 Me
thod of R
epla
cing Basic Mod
el QCPU
or H
igh
Perfor
mance
Model QCPU with U
niversal
Model QCPU
Appendix 3.4 Fun
ctions
APPENDICES
App
-
42
(3) Advantages and disadvantages when using the double-precision floating-point data of
the Universal model QCPU
TableApp.32 shows the advantages and disadvantages when executing the double-precision floating-point opera-
tion instructions in the Universal model QCPU.
If higher accuracy is required in floating-point operations, it is recommended to replace the instruc-
tions with the double-precision floating-point operation instructions.
*1: The processing speed of the double-precision floating-point operation instructions in the Universal model QCPU is higher
than that of floating-point operation instructions using internal double-precision operations in the High Performance
model QCPU.
TableApp.33 shows the comparison between single-precision and double precision floating-point data.
TableApp.34 Advantages and disadvantages when using the double-precision floating-point operation instructions
Advantage
Disadvantage
The results are more accurate than those of the
single-precision floating-point operation
instructions.
The instruction processing speed is slower than that of the single-
precision floating-point operation instructions.
*1
Double-precision floating-operation data use twice as many word device
points as single-precision floating-operation data.
TableApp.35 Comparison between single-precision and double precision floating-point data
Item
Single-precision floating-point
data
Double-precision floating-point
data
Word point required for data retention
2 words
4 words
Setting range
-2
128
<N
-2
-126
, 0,
2
-126
N<2
128
-2
1024
<N
-2
-1022
, 0,
2
-1022
N<2
1024
Precision (number of bits)
Mantissa
23
bits
52
bits
Exponent
8
bits
11
bits
Sign
1
bits
1
bits
Instruction processing
speed (Q04UDHCPU/
Q06UDHCPU) (Maximum)
Data comparison (Conductive
status) (LDE>= / LDED>=)
5.5
µs
9.0
µs
Data transfer
(EMOV/EDMOV)
0.019
µs
5.0
µs
Addition (3 devices)
(E+ / ED+)
0.0665
µs
9.2
µs
SIN operation (SIN/SIND)
5.7
µs
13.8
µs
Содержание melsec q00ucpu
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