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An Introduction to Programming
3.4.11
Master control function (MC and MCR instructions)
Instruction
MC
MCR
The MC instruction can be used on outputs (Y) and relays (M). n: N0 through N7
n: N0 through N7
The Master Control Set (MC) and Reset (MCR) instructions can be used to set conditions on
the basis of which individual program blocks can be activated or deactivated. In Ladder Dia-
gram format a Master Control instruction functions like a switch in the left-hand bus bar that
must be closed for the following program block to be executed.
Ladder Diagram
The "switch" does not have to
be programmed manually and
it is only actually displayed
during program execution in
Monitor mode.
Instruction List
0
LD
1
MC
4
LD
5
OUT
6
LD
7
OUT
8
MCR
10 LD
11 AND
12 OUT
In the example above the program lines between the MC and MCR instructions are only exe-
cuted when input X001 is on.
The section of the program to be executed can be specified with the nesting address N0
through N7, which allows you to enter multiple MC instructions before the closing MCR instruc-
tion. (See the FX Programming Manual for an example of nesting.) Addressing a Y or M device
specifies a make contact. This contact activates the program section when the input condition
for the MC instruction evaluates true.
FX Beginners Manual
Function
Master Control, sets a master control
condition, marking the beginning of a
program block
Master Control Reset, resets a master
control condition, marking the end of a
program block
0
N0
4
6
8
10
X001
N0
M10
X002
Y003
X003
Y004
N0
X002
X004
M155
Symbol
MC n
MCR n
X001
M10
X002
X003
X002
X004
The Basic Instruction Set
GX Works2 FX
F8
F8
MC
N0
M10
Y003
Y004
MCR
N0
M155
3 – 19
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