Question

For the following exercise, draw a Logical Ladder to solve the automation problem. After you press push button, you want Lights/LEDs behave as follows:

a. LED 1 will turn on, and stay on until LED 3 turns on

b. LED 2 will turn on only for 5 seconds

c. LED 3 will turn on after 8 seconds and stay on only for 1 second.

Answer 1

solution:

Objective: When Start push button pressed, the following excercise to be perform:

a.) LED 1 will turn on, and stay on until LED 3 turns on

b. ) LED 2 will turn on only for 5 seconds

c. ) LED 3 will turn on after 8 seconds and stay on only for 1 second.

Inputs : One turn ON switch (I:0/0) One turn OFF switch (I:0/1)

Outputs : LED 1 (o:0/0), LED 2(o:0/1), LED 3(0:0/2)

Additionally i used 3 memory locations (m:0/0,m:0/1 and m:0/2)

Ladder diagram :

when the start button pressed, m:0/0 will become high and stay high till stop button pressed

Immideatly LED1 in Rung 2, will get high.

LED 2 in Rung 3 will get high immediatly but it will go off after 5 seconds due to OFF Delay timer.  

Note : The NO LED 1 address switch placed in Rung 3 , to make sure that the LED will glow only after start button pressed.

Due to ON dealy timer in Rung 4 , the LED3 will on only after 8seconds and remains ON till 1 seconds.(m:0/1 will go high and stay high till stop button pressed)

The high state of LED 3 will make LED1 OFF.

All the LEDs will go off , when stop button is pressed, and later when start button is pressed , the process repeats.