282 Programmable Logic Controllers: Hardware and Programming
Example 13-2
In this example, an ON-delay timer is used to control the speed of
the operation of a BSL instruction. Figure 13-9 displays the PLC lad-
der diagram for Example 13-2. Placing a one in bit address B3/0 of the
data bit file causes the green pilot light (Green_PLT) to turn on. Then,
DN
TON
Timer ON Delay
Timer T4:0
Time base 0.1
Preset 30
Accum 0
EN
DN
0000
0006
0007
0002
0003
0004
0005
0001
Switch
This program will turn each light on then off every three seconds.
I:0
0
RES
Green_PLT
B3:0
0
BSL
Bit shift left
File #B3:0
Control R6:0
Bit address B3:0/0
Length 4
EN
DN
T4:0
DN
R6:0
UL
White_PLT
O:2
0
B3:0
0
1
Red_PLT
O:2
1
2
B3:0
1
O:2 B3:0
2
Reset
I:1
End
T4:0
Example 13-2
Figure 13-9. PLC ladder logic diagram for Example 13-2.