Mitsubishi Electric MELSEC FX Series - 3.3 Devices and Addresses

3 Configuration of Instruction
3.3 Devices and Addresses
52
FXCPU Structured Programming Manual
(Basic & Applied Instruction)
3.3 Devices and Addresses
A device is expressed by a device or an address.
Device
The device is expressed by a device name and a device number.
Address
An address is expressed by a method defined by IEC61131-3.
It is expressed as follows according to IEC61131-3.
• Position of memory area
This is the first classification to identify the position of memory area either by input, output and internal
where data is allocated.
X (X device) :I (Input)
Y (Y device) :Q (Output)
Device other than above :M (Internal)
•Size
The principle of expression method corresponding to device (method of expression for MELSEC) is as
follows.
Bit device :X (Bit)
Word device :W (Word), D (Double word)
• Classification
This is the second classification to identify the types of device that cannot be classified only by the above
position and size.
X or Y of a device does not classify.
Refer below for the expression corresponding to the device expression.
→ 7.3, Appendix A
Top
1st character:
position
2nd character: size
3rd character and
onwards: classification
Number
%
I Input (Omitted) Bit These are the numbers for
detailed classification. This
number is separated by "."
(period) from subsequent
numbers.
This number may be
omitted.
The number that indicates a
device number (decimal
number).
Q Output X Bit
M Internal W Word (16 bits)
D Double word (32 bits)
X 0 D 100
Device name Device numbe
r
%I
X 0 %M X 1 . 863
Position of
memory area
Size Classification Numbe
r