Week -2

Aim:

To make a simulink model of a doorbell using solenoid block.

To use a thermistor to sense the temperature of a heater & turn on or turn off the fan.

1.Door bell:

simulink model explaination:

• The pulae generator is useed to create square wave pulses at regular intervals.The block waveform parameters amplitude,pule width,period and phasee delay,determine the shape of the output waveform.

• The switch block used is controlled by external physical signal.If the external signal is greater than the thresold parameter then the switch is closed,otherwwise switch is open.
• The positive terminal of the switch is connected to switch and the negative terminal is connected to the electrical reference.
• The solinoid block is connected with switch and battery and we will get a complete electrical circuit.The port c is connected with mechanical reference.
• The ideal translational sensor is connected with solenoid block R to observe the movement of pllunger.
• Scope is connected with the ideal translational sensor to get the output.
• PS-Simulink converter is used to convert the physical signal to simulink signal.
• Solver Confifuration :Each physical network represented by a connected simscape blocks requires solver setting information for simulation.

2.Thermistor

Given inputs:

Temperature source :20`degree`C from 0 to 10 seconds,27`degree`C from 10 to 30 seconds,23`degree`C from 30 to 50 seconds.

Fan conditions:ON if the temperature above 25`degree`C,OFF otherwise

Simulink model:

Simuliink model explanation:

• Signal builder block is uded to input the values as per given conditions:

At point 1,Time =0 seconds ,Temperature =293 K

At point 2,Time =10 seconds ,Temperature =293 K

At point 3, Time =10 seconds,Temperature = 300 K

At point 4,Time =30 seconds ,Temperature =300K

At point 5,Time =30 seconds ,Temperature =296 K

At point 6,Time =50 seconds ,Temperature =296 K

• Controlled Temperature souurce represents an ideal source of thermal energy,that can maintain a controlled temperature difference regardless of the heat flow rate .The temperature difference is set by the physical signal port S.A positive temperature differeence causes the temperature at port B to be greateer than the temperature at port A.
• Thermistor is a tyype resistor whose resistor is based upon temperature.
• A linear resistor is used inorder to control the amount of current from the battery.
• The voltage sensor is used to convert the voltage measured between two points into physical signal.
• Voltage source which represents dc or ac.
• Electrical reference block is given
• Solver Configuration :Each physical network represented by a connected simscape blocks requires solver setting information for simulation.

Results:

Time period given is 2seconds to the pulse generator to open and close the switch.When the switch is closed the solenoid blocks receives electrical power from the battery and the plunger move from port R to c to hit the bell and produces the sound.

For 0 to 10 s fan is OFF condition because temperature is 293K which is below the thresold 298K .After 10 s temperature goes to 300K then the switch will be in ON condition as the temperature exceeds 298K .After 30s fan will turn OFF as the temperature comes down to 296K which is below the threshold temperature of 298K.