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Help me find solution for this logic

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Member level 2
Mar 11, 2006
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plz help me

hello guys
plz plz help me in solving these logics

You have been asked to program a PLC that is controlling a handicapped access door opener. The client has provided the electrical wiring diagram below to show how the PLC inputs and outputs have been wired. Button A is located inside and button B is located outside. When either button is pushed the motor will be turned on to open the door. The motor is to be kept on for a total of 15 seconds to allow the person to enter. After the motor is turned off the door will fall closed. In the event that somebody gets caught in the door the thermal relay will go off, and the motor should be turned off. After 20,000 cycles the door should stop working and the light should go on to indicate that maintenance is required.

A PLC is to control an amusement park water ride. The ride will fill a tank of water and splash a tour group. 10 seconds later a water jet will be ejected at another point. Develop ladder logic for the process that follows the steps listed below.
1. The process starts in ‘idle’.
2. The ‘cart_detect’ opens the ‘filling’ valve.
3. After a delay of 30 seconds from the start of the filling of the tank the tank ‘outlet’ valve opens. When the tank is ‘full’ the ‘filling’ valve closes.
4. When the tank is empty the ‘outlet’ valve is closed.
5. After a 10 second delay, from the tank outlet valve opening, a water ‘jet’ is opened.
6. After ‘2’ seconds the water ‘jet’ is closed and the process returns to the ‘idle state.


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