Allocation Of I/O Addresses - Mitsubishi MELSEC System Q Manual

Base Units
3.2.2

Allocation of I/O Addresses

To address inputs and outputs of a PLC in the program they must be undisputed labeled. This is
done by assigning a number to each input and output: the I/O address (see also chapter 4.1).
These addresses are counted in hexadecimal numbers. (Please read more about different
number systems later in chapter 4.3.)
A CPU of the MELSEC System Q automatically recognises the slots available in main and
extension base units and assigns addresses to the inputs and outputs accordingly.
However, the assignment can also be done with the aid of the programming software. Thus
slots can be left empty or addresses can be reserved for future extensions.
Extension cable
1st extension stage
2nd extension stage
The extension stage is set at the extension main unit with jumpers.
3 – 4
QB35B (5 slots are occupied
by I/O modules)
QB65B (4 slots are
occupied)
1
QB68B (8 slots are
occupied)
2
X110 X120 130
X11F X12F 14F
0 1 2 3
X00 X10 X20 Y40
X0F X1F X3F Y4F Y8F
5 6 7 8 9
90 B0 D0 YF0 100
AF CF EF YFF 10F
10 11 12 13 14
150 170 Y190 Y1A0 Y1B0
16F 18F Y19F Y1AF Y1BF
The MELSEC System Q
Slot No.
4
The I/O numbers
are assigned
according to the
number of physical
I/O on the relevant
slot.
Order of I/O
Y50
numbering
The slots are
numbered in
consecutive order.
The number of I/O
points for empty
slots is set in the
PLC parameters
(initial setting: 16)
15 16 17
MITSUBISHI ELECTRIC