Ladder Diagram of Time Control of a Traffic Signal (using RS Logix 500)

Operation:

When On push button is pressed, the process is started
1st red light is lit for 10 sec
Then yellow light is lit for 5 sec.
Then green light is lit for 10 sec.
And then process is repeated from step 1.

Working:

When On push button is pressed, red light is lit and On timer 1 starts for 10 sec. Holding contact keeps red light and timer ON. If we don't use holding contact then red light and timer keep ON until  On push button is pressed. When timer completes its 10 sec, its normally open link closes and its normally close link opens. In the same way 1st 3 rungs work. Then normally open link of On timer 2 resets all the timers and process starts again. This cyclic process remains On forever until the Off push button is pressed.

You might also like:

• Ladder Diagram of Latching of a contact in PLC
• Ladder Diagram of 2 motors running in cyclic order for life time (using RS logix 500)
• Boiler Control Using Control Area Network
• PLC based Automatic Filling of Large and Small Size Bottles (Bachelor Level Project)
• Semi Automated Radio Control Hovercraft (Bachelor level project)

Posted in: Ladder Diagrams, PLC Based Projects, Small Projects