2. Programming Concepts
2.6 PLC Bits, Nibbles, Bytes, Words, etc
For different control purposes, there are five types of values inside DVP-PLC for executing the
operations.
Numeric Description
Bit Bit is the basic unit of a binary number system. Range is 0 or 1
Consists of 4 consecutive bits, e.g. b3~b0. Range 0 ~ 9 in Decimal or 0~F in
Hex
Nibble
Consists of 2 consecutive nibbles, e.g. b7~b0. Range 00 ~ FF in Hex
Byte
Consists of 2 consecutive bytes, e.g. b15~b0. Range 0000 ~ FFFF in Hex
Word
Consists of 2 consecutive words, e.g. b31~b1. Range 00000000 - FFFFFFFF
in Hex
Double Word
Bit, nibble, byte, word, and double word in a binary system:

NB0NB1NB2NB3NB4NB5NB6NB7

BY3 BY2 BY1 BY0

W1

DW

W0

Double Word
Word
Byte
Nibble
Bit
2.7 Binary, Octal, Decimal, BCD, Hex
For fulllfilling different kinds of internal manipulation, DVP-PLC appies 5 foramts of number systems.
Each number system has its specific purpose and function described as below.
1. Binary Number, (BIN)
PLC internally calculates, operates, and stores the value in Binary format.
2. Octal Number, (OCT)
The external I/O points of DVP-PLC are numbered in octal format.
e.g.
External inputs: X0～X7, X10～X17, …, X377. (No. of device)
External outputs: Y0～Y7, Y10～Y17, …, Y377. (No. of device)
3. Decimal Number, (DEC)
DVP-PLC appies decimal operation in situations below:
z Set value for timers and counters, e.g. TMR C0 K50. (K value)
z No. of S, M, T, C, D, E, F, P, I devices, e.g. M10, T30. (No. of device)
z For use of operand in API instructions, e.g. MOV K123 D0. (K value)
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