Values And Constants (K, 16#) - Delta AH Series Operation Manual

5.2.16. Values and Constants (K, 16#)

- The explanation on data units which could be used in the system:
Name
Bit
Nibble
Byte
Word
Double word
Quadruple word
The relation among bits, nibbles, bytes, words, and double words in the binary system is shown below.
W 1
B Y 3
N B7 N B6
b31 b30 b29 b28 b27 b26 b25 b24b23 b22 b21 b20 b19 b18 b17 b16 b15 b14 b13 b12 b11 b10
- 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)
A bit is the basic unit in the binary system. Its state is either 1 or 0.
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.
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.
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.
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.
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.
D W
B Y 2
N B5 N B4 N B3
Ch a pt er 5 Un d er s t a n d in g Com m on D e v ic e s
Description
W 0
B Y 1 B Y 0
N B2 N B1 N B0
b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
D ouble w ord
W ord
B yt e
N ib ble
B it
5_
5 - 1 1