User manual

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Address (register)
Address refers to the location of memory being used. It can refer to the
external I/O module and internal memory.
An address is categorized into 1 bit, 16 bits (word), or 32 bits (double
word).
Bit
A bit is the minimum module required for calculation. It can be either
On (1) or Off (0).
Byte
A byte is made up of 8 bits. It can hold data values from 0 to 255. In
base 16, or hexadecimal, a byte can be expressed as 0 to FF. You
cannot have a value greater than 255 when using one byte.
Word
A word is made of 16 bits. It can hold data values from 0 to 65,535. In
base 16 a word can be expressed as 0 to FFFF.
NX PLCs set R, M, K, F, and W areas into word areas and can be
processed without any separate measures.
Double Word
A double word is made of 32 bits. It can hold data values from 0 to
4,294,976,295. In base 16, a double word can be expressed as 0 to
FFFFFFFF. In the D32LT, a double word is made up of two consecutive
word addresses as follows:
Double word address = Start word address + Next word address.
Scan Time
The CPU follows a procedure in which it 1) reads the inputs, 2)
processes the ladder program, and 3) updates the outputs. It
continually repeats this process. This 3-step process is called a “scan,”
and the time it takes to complete this process is the “scan time.” In a
typical PLC application, most of the scan time is used to process the
program. When programming, keep in mind that the scan time will
increase as you increase the number of inputs and outputs and/or the
size of the program
Edge
An edge is defined as the point when an input changes state. For
example, a rising edge occurs during the very first scan after the input
has changed from Off to On. A falling edge occurs after the input has
changed from On to Off.
Example: When using W003,
W003 (double word address) = W003 (start word address) + W004 (next word address)