Octal, Binary floatingćpoint – Rockwell Automation 1770, D17706.5.16 Ref Mnl DF1 Protocol Command User Manual
Page 201
11–5
Data Encoding
Publication 1770Ć6.5.16 - October 1996
Octal
The octal number system is another easy way to represent binary
data. This system uses the eight digits, 0 through 7. Each group of
three data bits represents one octal digit between 0 and 7. This factor
presents a slight conversion problem because bytes and words
usually contain an even number of bits. Thus, an 8-bit byte can have
an octal value between 0 and 377, while a 16-bit word can have an
octal value between 0 and 177777.
Each digit of an octal number has a place value that is a multiple
of 8. To convert from octal to decimal, multiply each octal digit
by its corresponding place value and add the results of the
multiplications.
Octal Representation of Decimal 239
1 x 2
1
= 2
1 x 2
0
= 1
1 x 2
2
= 4
0 x 2
1
= 0
1 x 2
0
= 1
1 x 2
2
= 4
1 x 2
1
= 2
1 x 2
0
= 1
1
1
1
0
1
1
1
1
3 x 8
2
= 192
5 x 8
1
= 40
7 x 8
0
=
7
= 357
8
239
10
Binary FloatingĆpoint
Use the binary floating-point numbering system when you want to
manipulate numbers outside of the range –32768 to +32768 or for a
resolution finer than one unit, for example 2.075.
SLC 5/03 OS300, SLC 5/04 OS400, and PLC-5 classic processors do
not support unnormalized, Not a Number (NaN), and infinity; PLC-5
enhanced processors support both NaN and infinity.
The valid range for a binary floating-point number is
$3.402824 x
10
38
to
$1.1754944 x 10
–38
.