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 and turn off the fan.

1. Door Bell:

simulink Model

Simulink Model explanation:

The pulse generator is used Tto create square wave pulses at regular intervals.The block waveform parameters,amplitude,pulse width,period and phase delay,determine 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,otherwise switch is open.
• The positive terminal of the switch is connected to switch and negative terminal is cnnected to the electrical reference.
• The solenoid 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 transitional sensor is connected with solenoid block R to observe the moment of the plunger.
• Scope is connected with ideal transitional sensor to get the output.
• PS-Simulink converter is used to convert the physical signal to sumilink signal.
• Solver Configuration: Each physical network represented by a connected simscape blocks requires solver setting information for simulation.

Result:

Door Bell:

Time period given is 2 sec,to the pulse generator to open and close the switch.When the switch is closed the solenoid block recieves electrical power from the battery and the plunger moves from port R to the bell and produces sound.

2. Thermistor

Given Inputs:

Temperature source: 20 ℃ from 0 to 10 sec, 27 ℃ from 10 to 30sec, 23℃ from 30 to 50sec.

Fan Condition: ON if the temperture above 25 ℃,OFF otherwise.

Simulink Model:

Simulink Model Explanation:

Signal Builder block is used to input the values as per given condition:

    At point 1, Time = 0sec, Temperature = 293K.

    At point 2, Time = 10sec, Temperature = 293K.

    At point 3, Time =10sec, Temperature = 300K.

    At point 4, Time = 30sec, Temperature = 300K.

    At point 5, Time = 30sec, Temperature = 296K.

    At point 6, Time = 50sec, Temperature = 296K.

• Controlled temperature source 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 cause the temperature at port B to be greater than the temperature at port A.
• Thermistor is a type of resistor whose resistance is based upon temperature.
• A linear resistor is used in order to control the amount of current from the battery.
• The voltage sensor is used to convert the voltage measured between two points into a physical signal.
• Voltage source which represents DC or AC.
• Electrical reference block is given.
• Solver confguration: Each physical network represented by a connected simscape blocks requires solver setting information for simulation.

 Result:

Thermistor:

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

  From the above conditions, all the values are evaluated.