Delta C2000 Series User Manual page 513

Chapter 16 PLC Functions Applications
Example 5: Interlocking control
The figure below shows an interlocking control circuit. Depending on which of the start
contacts X1, X2 is valid first, the corresponding output Y1 or Y2 will be actuated, and when
one is actuated, the other will not be actuated. This implies that Y1 and Y2 cannot be
actuated at the same time (interlocking effect). Even if both X1 and X2 are valid at the same
time, because the ladder diagram program is scanned from the top down, it is impossible for
Y1 and Y2 to be actuated at same time. This ladder diagram assigns priority only to Y1.
Example 6: Sequence control
If the NC contact of Y2 in the interlocking control configuration of example 5 is put in series
with the Y1 circuit, so that it is an AND condition for actuation of Y1 (see figure below), not
only is Y1 a condition for the actuation of Y2 in this circuit, the actuation of Y2 will also stop
the actuation of Y1. This configuration confirms the actuation order of Y1 and Y2.
C2000 Series
X3 Y2
X1
Y1
X4 Y1
X2
Y2
X1
Y1
X2
Y2
X1
Y 1
X3
X2
Y 2
X4
Y1
Y2
X3
Y2
X4 Y1
16-22
Y1
Y2