Mitsubishi MELSEC QS Series, Руководство пользователя

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3
SEQUENCE PROGRAM EXECUTION
3.7 Numeric Values which can be Used in Sequence Programs
3.7.3 BCD (Binary Coded Decimal)
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3.7.3 BCD (Binary Coded Decimal)
(1) BCD notation
BCD (binary coded decimal) is a numbering system in which one digit of DEC
(decimal) is expressed in BIN (binary).
Though it uses 4-bit representation like hexadecimal notation, it dose not use letters
A
H
to F
H
.
Table3.6 shows the numeric expressions of BIN, BCD and DEC.
(2) BCD numeric expression
CPU module registers (data registers, link registers, etc.) consist of 16 bits.
In case of 16 bits, 0 to 9999 can be specified in BCD.
POINT
The CPU module regards value stored in BCD as BIN.
For example, if 8000 is stored in BCD, the CPU module performs operation,
regarding the value as -32768.
When performing arithmetic operation between values stored in BCD and any
values in the CPU module, use the operation instruction of the BCD.
Table3.6 Comparison of BIN, BCD, and DEC Numeric Expressions
DEC (Decimal) BIN (Binary)
BCD
(Binary Coded Decimal)
0 0000 0
1 0001 1
2 0010 10
3 0011 11
4 0100 100
5 0101 101
6 0110 110
7 0111 111
8 1000 1000
9 1001 1001
10 1010 1 0000
11 1011 1 0001
12 1100 1 0010
Carry