Delta C2000 Series User Manual page 511

Chapter 16 PLC Functions Applications
16-4-4 Commonly-used basic program design examples
Start, stop, and protection
Some applications may require a brief close or brief break using the buttons to start and stop
equipment. A protective circuit must therefore be designed to maintain continued operation in these
situations; this protective circuit may employ one of the following methods:
Example 1: Priority stop protective circuit
When the start NO contact X1=On, and the stop NC contact X2 Off, Y1=On; if X2=On at
this time, coil Y1 will no longer be electrified, and this is therefore referred to as priority stop.
Example 2: Priority start protective circuit
When start NO contact X1=On, and the stop NC contact X2 Off, Y1=On, and coil Y1 will be
electrified and protected. At this time, if X2=On, coil Y1 will still protect the contact and
continue to be electrified, and this is therefore priority start.
C2000 Series
MPS
MRD
MPP
X2
Y1
STOP
X1
START
X2
X1
START STOP
Y1
16-20
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Y1
Y1