Chapter 7 Second Development Platform VP3000
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Byte
Consist of two consecutive nibbles, that is, eight bits, b7–b0. To indicate a
value which range between 00–FF in hexadecimal.
Word
Consist of two consecutive bytes, that is, 16 bits, b15–b0. To indicate a value
which range between 0000–FFFF in hexadecimal.
Double Word
Consist of two consecutive words, that is, 32 bits, b31–b0. To indicate a
value which range between 00000000–FFFFFFFF in hexadecimal.
The bit, nibble, byte, word, and double word in a binary system:
Octal Number (OCT)
The external input and output terminals of DVP-PLC are numbered in octal format.
Example:
External input: X0–X7, X10–X17, ... (No. of device)
External output: Y0–Y7, Y10–Y17, ... (No. of device)
Decimal Number (DEC)
The timing of decimal applications in PLC system is as follows:
As setting values for timer (T), counter (C), e.g. TMR C0 K50. (constant K)
The numbers of M, T, C, D devices, e.g. M10, T30. (No. of device)
As operands in application instructions, e.g. MOV K123 D0. (constant K)
Binary-Coded Decimal (BCD)
Take one nibble or four bits to indicate a decimal value, so that data of consecutive 16 bits can
indicate a four-nibble decimal value. Mainly used in reading the input values from DIP switches
or outputting the data to a 7-segment display.
Hexadecimal Number (HEX)
The timing of hexadecimal applications in PLC system is to use it as operands in application
instructions, e.g. MOV H1A2B D0. (H constant)
Constant K
A decimal number in PLC system is generally preceded by K, e.g. K100 indicates that it’s decimal
and the value is 100.
Exception: if K is used with a X / Y / M / S device, a data in nibble, byte, word or double word
format will be formed. Example: K2Y10, K4M100. K1 represents a 4-bit combination, and K2–K4
represents 8-bit, 12-bit and 16-bit combinations individually.
H Constant
A hexadecimal number in PLC system is generally preceded by H, e.g. H100 indicates that it’s
hexadecimal and the value is 100.
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