Mitsubishi MELSEC QCPU User Manual

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MELSEC-Q/QnA
3 CONFIGURATION OF INSTRUCTIONS
3.2.4 Using real number data
Real number data is 32-bit floating decimal point data used with basic instructions and application
instructions.
Only word devices are capable of storing real number data.
Instructions which deal with real numbers designate devices which are used for the lower 16 bits
of data. Real numbers are stored in the 32 bits which make up (designated device number) and
(designated device number + 1).
The 2 points R100 and R101
(32 bits) are used
M0
EMOV R100 D0
The 2 points D0 and D1 (32 bits) are used
Real number data transfer
REMARK
1) In sequence programs, real numbers are designated by E .
Floating decimal point data uses two word devices and is expressed in the following manner:
1. [Variable part] × 2 [exponent part]
The bit configuration and meaning of the internal representation of floating decimal point data is as
follows:
b31 b30
to
b23
b22 b16
to
b15 b0
to
b31
Sign for variable part
b23 to b30
Exponent part
b0 to b22
Variable part
• Sign for variable part The sign for the variable part is represented at b31.
0: Positive
1: Negative
• Exponent part The n of 2
n
is represented from b23 to b30.
Depending on the BIN value of b23 to b30, the value of n is as follows.
b23 to b30 FF
H
FE
H
FD
H
81
H
80
H
7F
H
7E
H
02
H
01
H
00
H
n
Nonnumeric
127 126 2 1 0 -1 -125 -126
Nonnumeric
• Exponent part The 23 bits from b0 to b22, represents the XXXXXX... at binary
1.XXXXXX....
POINT
• The CPU module floating decimal point data can be monitored using the
monitoring function of a peripheral device.
• When this is expressed as 0, all data from b0 to b31 will be 0.
• The setting range of real numbers is 0 and ±2
-126
| value | < 2
128
.
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Mitsubishi MELSEC QCPU Specifications

General

Brand	Mitsubishi
Model	MELSEC QCPU
Category	Controller
Language	English