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.

Assume remaining parameters.

ANSWER:-

Parameters for pulse generator:-

Explanation:-

• We have used pulse generator to create square wave input signal at regular intervals ,and using parameters like amplitude,time period ,pulse width and phase delay in pulse generator we can get the required output signal.
• 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 & INPUT WAVEFORMS)

• Time period given is 2 seconds to the pulse generator to open and close the switch is closed then solenoid blocks receives electrical power from the battery and the plunger move from port R and C to it gets into touch the bell and the sound will be heared.

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.

ANSWER:-

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

By finding the 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.From the below figure you can observe the input which we have given to the signal builder to find out the threshhold value.

• The above figure was the input waveform which we have given to find out the threshold value.

• so,threshold value is 5.72*10^-22.
• hence this condition when proved 25 degree fan was ON Condition otherwise OFF condition.
• Controlled temperature sourse 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 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 & Mechanical reference block is given to evaluate .
• Solver configuration ,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.

• Thus we have created a simulink and simcape blocks to build an model to run a fan with mentioned room temperature settings and mentioned waveform graphs which was before input and after output and then the graph to find out threshold value which is important to match the given conditions.