Week -2

1. Make a Simulink model of Doorbell using solenoid block with the following details:

   In the above arrangement, when the switch is closed the electromagnet receives electrical power from the battery and pulls the metal arm to hit the bell producing sound.

   Create a situation where the switch is closed for 2 seconds and then released. Observe the physical movement of the plunger.

SOLUTION

DoorBell Simulink Diagram

Simulink Model Explanation:

• The pulse generator is used to create square wave pulses at regular intervals.the block diagram wave form parameters amplitude ,pulse width,period and phasedelay,determine the shape of the output waveform.

• The Switch block used is controlled by external physical signal is greater then the thresold parameter then the switch is closed,otherwise switch is open.
• The positive terminal of the switch is connected to switch and the negative terminal is connected to the electrical reference.
• The solenoid block is connected width switch and battery and we will get a complete electrical circuit. The port C is connected width mechanical reference.
• The ideal translational sensor is connected width solenoid block R to observe the movement of the plunger.
• Scope is connected width the ideal translational sensor to get the output.
• PS-Simulink converter is used to convert the physical signal to simulink signal.
• Solver configuration,each physical network represented by a connected simscape blocks requires solver setting information for simulation.

RESULT:

OUTPUt AND INPUT Waveforms:

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

2. Use a thermistor to sense the temperature of a heater & turn on or turn off the fan as per the below conditions:

Temperature source: 20 °C from 0 to 10 seconds, 27 °C from 10 to 30 seconds, 23 °C from 30 to 50 seconds

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

Solution:

Simulink Diagram

Simulink Model Explanation:

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

1. At point,Time=0 seconds,Temperature=20 °C
2. At point,Time=10 seconds,Temperature=20 °C
3. At point,Time=10 seconds,Temperature=27 °C
4. At point,Time=30 seconds,Temperature=27 °C
5. At point,Time=30 seconds,Temperature=23 °C
6. At point,Time=50 seconds,Temperature=23 °C

find threshold value,

• Fan conditions: ON if the temperature above 25 °C, OFF otherwise
• So First set the input 25 degree in signal builder then save and important to connect the output from current sensor - ps to simulink converter - scope to get the threshold value. i will attach the waveform.

• so,threshold value is 5.72*10^-22.
• helce this condition when proved 25 degree C is fan ON otherwise OFF.
• Controlled temperature sourse represents an ideal source of thermal energy.that can maintain a controlleed temperature difference regardless of the heat flow rate.the temperature difference is set by the physical sigbal port S.A positive temperature difference causes the temperature at port B to be greater then the temperature at port A.
• Thermistor is a type resistor whose resistance is based upon temperature.
• The current sensor is used to convert the current measured between two points into a physical signal.
• Voltage source which represents 12v dc.
• Electrical refrence block is given.
• Solver configuretion ,Each physical network represent by a connected simscape blocks requires solver setting information for simulation.

RESULT:

From the above conditions ,all the values are evaluated.

• Fan conditions: ON if the temperature above 25 °C, OFF otherwise.