Page 269 - Electric Drives and Electromechanical Systems

266 Electric Drives and Electromechanical Systems

Table 10.4 Instructions for the ladder logic
shown in Fig. 10.16
LD X0
OR X1
OR X2
AND X3
AND X4
OR X5
OUT Y1

FIG. 10.17 The use of a PLC timer, to extend the input pulse, X0.

timer is inhibited by the normally closed contact X0. When the input is deactivated the
timing cycle is initiated, and, following timeout, the output of T450 becomes active,
breaking the connection to Y1 and the timer and releasing the output and resetting the
timer. The instructions for this example are shown in Table 10.5.

Table 10.5 Instructions for the pulse extender ladder
logic shown in Fig. 10.17.
LD XO Input
OR Y1
ANI T450
OUT Y1 Output
ORI X1
AND T450
K20 Timer period