179
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
7 Basic Instruction
7.9 MC, MCR
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
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Speci
fied t
h
e
D
evi
ce &
C
onst
a
nt
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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
7.9
MC, MCR
Outline
When MC instruction is executed, the bus line (LD or LDI point) is moved to a position after MC contact.
The bus line can be returned to the original position by MCR instruction.
By changing a device (Y or M) number, MC instruction can be used as many times as necessary.
If a same device number is used twice, however, it results in the double coil operation in the same way as
OUT instruction.
1. Instruction format
→
For the number of steps of MC instruction, refer to Section 7.15.
2. Applicable devices
S
: Except special auxiliary relays (M)
Explanation of function and operation
1. MC and MCR instructions (denotes the start of a master control block and denotes the end
of a master control block)
When MC instruction is executed, the bus line is moved to a position after MC contact.
Drive instructions connected to the bus line after MC contact execute each operation only when MC
instruction is executed, and do not execute the operation when MC instruction is not executed.
In the program example below, the instructions from MC to MCR are executed as they are while the input
X000 is ON.
However, while the input X000 is OFF, each driven device offers the following operation:
Timers (except retentive type timers) and devices driven by OUT instruction: Turn OFF.
Retentive type timers, counters and devices driven by SET/RST instruction: Hold the current status.
The expressions of circuit programs used to explain operations are circuits (for reading or monitoring) of GX
Developer.
Instruc-
tion
Bit Devices
Word Devices
Others
System User
Digit Specification
System User
Special
Unit
Index
Con-
stant
Real
Number
Charac-
ter String
Pointer
X Y M T C S D
.b KnX KnY KnM KnS
T
C
D
R U
\G
V
Z Modify K
H
E
"
"
P
MC
3
S
MCR
There are no applicable devices.
MC
Master Control
Basic Instruction
MC
−
Continuous
Operation
Pulse (Single)
Operation
Mnemonic
Operation Condition
MCR
Master Control
Reset
Basic Instruction
2 steps
MCR
−
Continuous
Operation
Pulse (Single)
Operation
Mnemonic
Operation Condition