Delta AH Series User Manual

Chapter 5 Understanding Common Devices
5-11
5_
5.2.16. Values and Constants (K, 16#)
- The explanation on data units which could be used in the system:
Name
Description
Bit
A bit is the basic unit in the binary system. Its state is either 1 or 0.
Nibble
A nibble is composed of four consecutive bits (e.g. b3~b0). Nibbles can be used to
represent 0~9 in the decimal system, or 0~F in the hexadecimal system.
Byte
A byte is composed of two consecutive nibbles (i.e. 8 bits, b7~b0). Bytes can be used to
represent 00~FF in the hexadecimal system.
Word
A word is composed of two consecutive bytes (i.e. 16 bits, b15~b0). Words can be used to
represent 0000~FFFF in the hexadecimal system.
Double word
A double word is composed of two consecutive words (i.e. 32 bits, b31~b0). Double words
can be used to represent 00000000~FFFFFFFF in the hexadecimal system.
Quadruple word
A quadruple word is composed of four consecutive words (i.e. 64 bits, b63~b0). Quadruple
words can be used to represent 0000000000000000 – FFFFFFFFFFFFFFFF in the
hexadecimal system.
The relation among bits, nibbles, bytes, words, and double words in the binary system is shown below.
b31b30 b29 b28 b27b26 b25 b24
b23
b22 b21 b20b19 b18 b17b16 b15b14
b13
b12b 11 b10
b9 b8
b7
b6
b5 b4
b3
b2 b1 b0
NB0NB1NB2NB3NB4NB5NB6NB7
BY3 BY2 BY1 BY0
W1
DW
W0
Double word
Word
Byte
Nibble
Bit
- The PLC uses four types of values to execute the operation according to different control purposes. The functions of
these values are illustrated as follows:
1. Binary number (BIN)
The PLC adopts the binary system to operate the values.
2. Decimal number (DEC)
The decimal number in the PLC is used as;
 the setting value of the timer (T) or the setting value of the counter (C/HC). For example, TMR C0 50
(constant K).
 the device number. For example, M10 and T30 (device number)
 the number before or after the decimal point. For example, X0.0, Y0.11, and D10.0 (device number).
 the constant K: It is used as the operand in the applied instruction. For example, MOV 123 D0 (constant K).
3. Binary-coded decimal (BCD)
A decimal value is represented by a nibble or four bits, and therefore sixteen consecutive bits can represent a
four-digit decimal value.
4. Hexadecimal number (HEX)

Delta AH Series Specifications

General

Brand	Delta
Model	AH Series
Category	Controller
Language	English