NAiS FP1 User Manual

255
8-9. Terminology
In general, programmable controllers work with binary numbers in one form
or another to represent various codes or quantities. The binary number
system uses the number 2 as the base and the only allowable symbols are “0”
and “1”. There are no 2s, 3s, etc. Each digit of a binary code is called as
“bit”. “Bit” means “binary digit”. A group of 8 bits is called a “byte” and a
group of 16 bits (two bytes) is called a “word”.
The binary number “0000000000101011” is expressed in decimal as follows:
1 × 2
0
+ 1 × 2
1
+ 0 × 2
2
+ 1 × 2
3
+ 0 × 2
4
+ 1 × 2
5
+
.....
+ 0 × 2
15
= 1 + 2 + 0 + 8 + 0 + 32 +
.....
+ 0
= 43
One of the codes expressed in binary. BCD is a binary code in which each
decimal digit from 0 to 9 is represented by four binary digits (bits). The four
positions have a weighted value of 1, 2, 4, and 8, respectively, starting with
the least significant bit. A thumbwheel switch is specified as a BCD device,
and when connected to a programmable controller, each decimal digit
requires four inputs.
[EXAMPLE]
A number system that uses two symbols, “0” and “1”. Each digit position has
a weighted value of 1, 2, 4, 8, 16, 32, 64, and so on begining with the least
significant (right-most) digit.
The sum of N0 through Nn is the decimal equivalent of the number in base
“2”.
• Z2
Zn •• • • Z3
Z1
Z0
Bit position
Z0 × 2
0
= N0
• 2
n •• • • 3
1
0 Base = 2
Z1 × 2
1
= N1
Z2 × 2
2
= N2
Z3 × 2
3
= N3
Zn × 2
n
= Nn
•
•
•
0
0
1
1
Digit position
Decimal
9
3
7
2
0
0
11
1
8
1
000
30
1
15
01
12
1
1
0
0
74
00
Bit position
BCD
•• •• •• ••
0
0
11
0
8
0
111
30
0
15
0
1413
0
12
0
10
0
9
0
21
0
74
0
6
1
5
Bit position
Binary data
Most significant bit
(MSB)
Least significant bit
(LSB)
byte byte
word
binary:
Binary Coded Decimal (BCD):
binary number system:

NAiS FP1 Specifications

General

Brand	NAiS
Model	FP1
Category	Controller
Language	English