73
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
4 Devices in Detail
4.2 I/O Relays [X, Y]
1
In
troduct
io
n
2
Ov
e
rv
ie
w
3
In
st
ru
ct
ion
Li
st
4
D
evi
ce
s
in
De
ta
il
5
Speci
fied t
h
e
D
evi
ce &
C
onst
a
nt
6
Bef
o
re
Pr
ogr
a
m
m
ing
7
Bas
ic
In
st
ru
cti
o
n
8
FNC0
0
-FNC0
9
P
ro
g
ra
m F
lo
w
9
FNC1
0
-FNC1
9
M
ov
e
&
C
om
par
e
10
FNC
20-
FNC
2
9
Ar
ith.
&
Logi
c
O
per
at
io
n
4.2
I/O Relays [X, Y]
Some numbers of input relays and output relays are specific ones secured in the main unit, and other
numbers are assigned to extension devices in the connection order. Because these numbers are octal,
numeric values such as "8" and "9" do not exist.
4.2.1
Numbers of I/O relays
The table below shows input relays (X) numbers and output relays (Y) numbers (Numbers are assigned in
octagon.)
4.2.2
Functions and roles
Examples of terminal names and wiring (sink input) are for FX
3U
Series PLC.
FX
3UC
PLC
Model
name
FX
3UC
-32MT-LT
When
extended
256
points
in total
Input
X000 to X017
16 points
X000 to X357
240 points
Output
Y000 to Y017
16 points
Y000 to Y357
240 points
FX
3U
PLC
Model
name
FX
3U
-16M
FX
3U
-32M
FX
3U
-48M
FX
3U
-64M
FX
3U
-80M
When
extended
256
points
in total
Input
X000 to X007
8 points
X000 to X017
16 points
X000 to X027
24 points
X000 to X037
32 points
X000 to X047
40 points
X000 to X367
248 points
Output
Y000 to Y007
8 points
Y000 to Y017
16 points
Y000 to Y027
24 points
Y000 to Y037
32 points
Y000 to Y047
40 points
Y000 to Y367
248 points
The PLC outputs signals to external loads through
output terminals. Contacts for external output
(output devices such as relay contacts, TRIACs and
transistors) of output relays are connected to output
terminals inside the PLC. An output relay has many
electronic NO contacts and NC contacts. These
contacts can be arbitrarily used inside the PLC.
Differences in operations between external output
contacts (output devices) and internal contacts are
explained on the next page.
The PLC receives signals from external switches
through input terminals.
An input relay (X) connected to an input terminal
inside the PLC is an electronic relay isolated
optically, and has many NO contacts and NC
contacts. These contacts can be arbitrarily used
inside the PLC.
These input relays cannot be driven by a program.
X000
X000
Y000
X001
Program example
Y000
X000
X000
PLC
Y000
Y000
NO contact
NC contact
External power
supply
Y000
COM1
Load
Output terminal
X000
0V
Input
signal
Input
terminal
24V
S/S