Chapter 6 PLC Programming 107
I:0/0 I:0/1
L1 L2
O:0/1 O:0/0
Figure 6-6. Incorrect ladder diagram. Only one output can be connected in
series with a group of contacts.
I:0/0 I:0/1 I:0/2
L1 L2
O:0/0
I:0/0 I:0/3 I:0/5
I:0/3
I:0/4 O:0/1
Correct
Incorrect
SW TSW
L1 L2
1
2
3
M1
M1
M1
Green pilot light
Red pilot light
Motor #1
2, 3
Figure 6-7. Flow in ladder diagrams is from left to right.
Figure 6-8. Placing comments on the ladder diagram.