Mitsubishi Electric 700 Series Programming Manual page 141

Sequence Instructions
Note the following when nesting the instructions.
(1) The instructions can be nested to a level of eight (N0 to 7). When nesting them,
use MC from lower to higher nesting (N) numbers and MCR from higher to lower
numbers. In the opposite order, the PLC function cannot perform normal
operation since the instructions cannot be nested.
Display in ladder mode
A
B
Nesting numbers of MCR are
opposite.
(2) When the MCR instructions are gathered in one place in the nesting structure, all
master controls can be terminated by one lowest nesting (N) number.
136
Actual operation ladder
Since buses cross each other, normal
master control ladder cannot be created.