Chapter 6 PLC Programming 105
SW1 SW2 LS1
M1
L1 L2
I:0/0 I:0/1 I:0/2
L1 L2
O:0/0
I:0/0 I:0/1 I:0/2
L1 L2
O:0/0
Figure 6-1. A simple relay logic diagram.
Figure 6-2. The PLC ladder diagram.
Figure 6-3. Incorrect ladder diagram. Coils must appear at the
end of the rung.