PLC $$ Controlled Elevator System

Programmable Logic Controllers are very powerful digital controllers that have replaced relay systems in industrial and automatic applications. As a junior technician in industrial automation, you have been tasked to design a proof of concept of a PLC$-$controlled elevator design for a system with the following specifications:

$$ A four$-$level elevator $($G $$ floor, L$1,$ L$2,$ L$3)$

$$ Two DC motors for up and down motion

$$ Level sensors

$$ Level indicators

$$ An emergency button and emergency buzzer alarm

$$ An emergency lighting

$$ Main DC power supply

The design must be simulated on licence$-$free software, typically CODESYS.

Source: N$.$Y$.$ Matanga, $(2024)$

System Functional Description :

The design must be simulated using CODESYS or any similar licence$-$free PLC simulation software.

$$ The system has four floors: Ground floor, Level $1,$ Level $2$ and Level $3$

$$ It is made of one H$-$bridge$-$controlled DC motor that can move up or down $($M$1)$

$$ An additional H$-$bridge$-$controlled DC motor for opening and closing of the elevator door $($M$2)$

$$ The elevator has four commands buttons $($C$0,$ C$1,$ C$2$ and C$4)$ for each floor

$$ Command buttons are normally open buttons configured in LOW mode

$$ Only one button can be pressed at a time.

$$ When a floor button is pressed, the motor runs for $6$ seconds to open the door and then closes.

$$ The elevator has four level sensors to detect whether the elevator has reached a specific floor. Consider that when each sensor is triggered, a HIGH$-$level logic output is triggered otherwise, the level remains LOW.

$$ Each motor run per floor takes $8$ seconds whether it is an upward or downward motion.

$$ The motor runs forward or reverse depending on which floor is pressed and on which it is currently.

$$ The motor should reject the command if the same floor number is pressed.

$$ Each time a floor is reached. The level buzzer runs for a second when the door opens and when it closes.

$$ The elevator has four distinct level indicators for each floor $($G$1,$ L$1,$ L$2,$ L$3)$ that switch on by an active HIGH$-$level logic output.

$$ An emergency buzzer runs each time a user presses the emergency button.

$$ Should the door open, the emergency should immediately stop ringing.

$1\mathrm{.}1.$ Provide a detailed explanation of the operation an H bridge$-$controlled DC motor with a support illustrative diagram.

$(7$ marks$)$

$1\mathrm{.}2.$ Give a brief report of potential hardware $($sensors$,$ indicators, actuators, and power sources$)$ that could be used for the current system as a mini$-$proof of concept project. Include support pictures and justification.

$(18$ marks$)$

$2\mathrm{.}1.$ Using a PLC controller of your choice, provide a wiring diagram of the proof$-$of$-$concept elevator system. Give the specifications of the controller you have selected.

$(10$ marks$)$

$2\mathrm{.}2.$ Use a Sequential Function Chart or Flowchart to explain the operation logic of the full process. $(10$ marks$)$

$3\mathrm{.}1.$ Draw the Ladder Diagram representation of the full process.

$(15$ marks$)$

$3\mathrm{.}2.$ Explain the functions of each rung $($network$)$ in the ladder diagram

$(10$ marks$)$