Single/Double-Precision Real Number Data - Mitsubishi Electric M800VW Series Programming Manual

M800V/M80V Series PLC Programming Manual (1/2)
6 Explanation of Instructions and Functions
6.3 Data Designation Method

6.3.4 Single/Double-Precision Real Number Data

Real number data is floating decimal point data used by basic instructions and application instructions.
Only word devices are capable of storing real number data.
 Single-precision real number (single-precision floating-point data)
Instructions that deal with single-precision floating-point data designate devices to be used for the lower 16 bits.
Single-precision floating-point data is stored in 32 bits composed of "designated device number" and "designated device
number + 1".
M0
In a sequence program, floating-point data is designated by E ○ .
Single-precision floating-point data is represented as follows, using two word devices.
[Exponent]
[Sign] 1.[Mantissa] × 2
The bit configuration and meaning for the internal representation of single-precision floating-point data are described below:
b31 b30 to b23 b22
b31 b23 to b30
Sign Exponent
 Sign: b31 shows the sign.
0: Positive
1: Negative
 Exponent: b23 to b30 show n of 2n. As shown in the following, n corresponds to the BIN values of b23 to b30.
b23 to b30 FFH FEH
n 127
Not used
 Mantissa: 23 bits from b0 to b22 show the value of "XXXXXX..." when the data is "1.XXXXXX..." in binary.
EMOV R100 D0
Designation of 2 points of word devices D0 and D1 (32 bits)
Designation of 2 points of word devices R100 and R101 (32 bits)
Single-precision floating-point data transfer instruction
to b16 b15
b0 to b22
Mantissa
FDH 81H 80H
126 2 1
to b0
7FH 7EH 02H
0 -1 -125
103
01H 00H
-126
Not used
IB-1501667-B