Mitsubishi QCPU (Q Mode), Руководство пользователя

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MELSEC-Q
4 SEQUENCE PROGRAM CONFIGURATION AND EXECUTION
CONDITIONS
(b) Storing "0.75"
(0.75) (0.11) (1.100.... 2 )
10 2
-1
2
Mantissa code Positive to 0
Characteristic -1 to 7E
H
to (01111110)
2
Mantissa (100 00000 00000 00000 00000)
2
Therefore, the data expression will be 3F400000
H
, as shown below.
Code Characteristic Mantissa
0 0 1 1 1 1 1 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
3 F 4 0 0 0 0 0
POINT
(1) The monitor function for GX Developer permits monitoring the real number data
of the High Performance model QCPU.
However, if an attempt is made to monitor the data that cannot be represented
as a real number, e.g. "FFFF
H
", "_____" is displayed.
(2) For a "0" value, "0" will be indicated at all the b0 to b31 bits.
(3) It is possible to select either "Perform internal arithmetic operation in double
precision" or "Do not perform internal arithmetic operation in double precision"
with the floating point arithmetic processing on the PLC parameter's PLC
system settings. (The result of the operation will be short precision regardless
of the floating point arithmetic processing setting.)
It is recommended that "Do not perform internal arithmetic operation in double
precision" is selected if increased speed for the real arithmetic operations is
required, and "Perform internal arithmetic operation in double precision" is
selected if precision is required when applying compatibility with conventional
equipment.
• Only internal arithmetic operations will be performed at double precision (64-
bits) when "Perform internal arithmetic operation in double precision" is
selected (default setting.)
Precision will be increased for commands that use many real arithmetic
operations with internal arithmetic operations, such as the SIN command and
COS command, when double precision is set.
• Real arithmetic operations will be performed faster owing to the internal
arithmetic operations being performed with short precision (32-bit) when "Do
not perform internal arithmetic operation in double precision" is set, and there
are also cases where a certain amount of precision will be lost.
To turn off "Perform
internal arithmetic
operations in double
precision", uncheck
the check box.