Mitsubishi Electric MELSEC iQ-F FX5 Programming Manual page 160

Processing details
These instructions create program with efficient ladder switching by opening/closing common buses in ladders.
Ladder using master control is illustrated below.
(Left: Display on the engineering tool, Right: Actual operation)
X0
MC
N1 M0
X1 X3 M7
M5
X6 X4
X10
(1) Executed only when X0 is on
■MC
• When the execution command of the MC instruction turns ON at the start of master control, the operation result between
the MC and MCR instructions is as per the instructions (according to ladder). When the execution command of MC
instruction turns OFF, the operation result between the MC and MCR instructions becomes as follows.
Device
Timer
Counters, retentive timers
Devices in OUT instruction
Devices in SET and RST instructions
Devices in SFT(P) instruction
Devices in basic instructions and
applied instructions
When an instruction (e.g. FOR to NEXT instructions etc.) not requiring NO contact instruction is programmed
in a ladder using master control, the CPU module executes that instruction regardless of the execution
command of this instruction.
• With this instruction, the same nesting (N) number can be used as many times as necessary by changing the device
specified by (d).
• When this instruction is ON, the coil of the device specified by (d) turns ON. Also, the coil becomes a double coil when the
same device is used by the OUT instruction, for example. So, do not use the device specified by (d) in other instructions.
■MCR
• This instruction indicates the end of the master control range by the master control release instruction.
• Do not prefix this instruction with NO contact instruction.
• Use these (MC and MCR) instructions with same nesting number as a pair. Note, however, that when this instruction is
nested at a single location, all master controls can be ended by just one (N) number, the smallest number. (Refer to
Caution.)
6 SEQUENCE INSTRUCTIONS
158
6.5 Master Control Instruction
N1 M0
Y20
Y30
MCR N1
Y40
Device status
The count value becomes 0, and both coils and contacts turn OFF.
Coils turn OFF but the current status of both count values and contacts is
maintained.
Forcibly turned OFF.
Current status is maintained.
X0
MC
N1 M0
X1 X3 M7
M5
X6 X4
X10
N1 M0
Y20
(1)
Y30
MCR N1
Y40