AutomationDirect DL105, Руководство пользователя

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Appendix
G
Numbering
S
ystems
G--4
Numbering Systems
DL105 PLC User Manual, 3rd Edition
Octal Numbering System
Many of the early computers used the octal numbering system for compiled
printouts. Today, the PLC is about the only device that uses the Octal numbering
system. The octal numbering system uses 8 values to represent numbers. The
values are 0--7 being Base 8. Table 4 shows the first 32 decimal digits in octal. Note
that the octal values are 0--7, 10--17, 20--27, and 30--37.
Octal Decimal Octal Decimal
0 0 20 16
1 1 21 17
2 2 22 18
3 3 23 19
4 4 24 20
5 5 25 21
6 6 26 22
7 7 27 23
10 8 30 24
11 9 31 25
12 10 32 26
13 11 33 27
14 12 34 28
15 13 35 29
16 14 36 30
17 15 37 31
Table 4
This follows the Direct LOGIC PLCs. Refer to the bit maps in Chapter 4 and notice
that the memory addresses are numbered in octal, as well as each bit. The octal
system is much like counting in the decimal system without the digits 8 and 9 being
available.
The general format for four digits of the octal number is:
(d x 8
0
) + (d x 8
1
) + (d x 8
2
) + (d x 8
3
)
where “d“ means digit. This is the same format used in the binary, decimal, or
hexadecimal systems except that the base number for octal is 8.