Mitsubishi 00JCPU, Руководство пользователя

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CHAPTER2 SEQUENCE PROGRAMS
2
3
2.4 D
ata Used in Sequence Progr
ams
2.4.4 R
eal
number (
F
loating-point data)
(c) Performing internal operations in double precision
Note2.7
Select the checkbox for the Floating-point arithmetic processing parameter in the PLC system tab of the PLC
parameter dialog box. (The checkbox is selected by default.)
Note7
Operation results are represented in single-precision floating-point data regardless of the parameter setting.
When the parameter is selected, only internal operations are performed in double precision (64 bits).
Determine whether to select the "Perform internal arithmetic operations in double precision" checkbox
according to the purpose as described below.
1) Selecting the checkbox
Select the checkbox when accuracy is required to ensure compatibility with the existing models.
When instructions that perform many real number operations internally, such as the SIN or COM instruction,
are used, data accuracy increases by selecting this checkbox.
2) Not selecting the checkbox
Do not select the checkbox when the real number operation processing time needs to be reduced.
Since internal operations are performed in single precision (32 bits), the operation speed is improved.
However, data accuracy may decrease.
●
The real number data in the CPU module can be monitored by monitor operation from GX Developer.
Note that if the data to be monitored cannot be represented in real number (for example, "FFFF
H
"), "-" will be displayed.
●
To represent "0", all bits from b0 to b31 must be "0".
Figure 2.49 PLC system setting
Note7
Deselect the checkbox
here if internal operations
are not necessary to be
performed in double precision.
Note2.7
The "Perform internal arithmetic operation in double precision" checkbox cannot be selected for the Basic model
QCPU, Process CPU, and Redundant CPU.
Basic
Process
Redundant