Week -2
Q-1. Make a Simulink model of Doorbell using solenoid block with the following details:
ANS-
*In this model I have used following blocks with the functions:
1. Solenoid-
A solenoid converts electrical energy into mechanical work, when the electrical energy flow through this solenoid coil strong magnetic field/ flux created due to this magnetic field it created force.
2. Battery-
It gives the supply to solenoid.
3.Switch-
Switch is used for making the complete path. If the external physical signal is greater than threshold value then switch is closed.
4. Pulse Generator-
The pulse generator is used to generate square wave pulse at regular intervals. Pulse generated from PG is converted to simulink to physical signal and given to switch for perform switch function.
Following values are given to pulse generator- Amplitude-1, Period-10 sec, Pulse width-20%, Phase delay- 2.
5. Ideal Translation Motion Sensor-
The physical movement done by solenoid & it sense by ideal translation sensor.
6. Scope-
It is used to see the output of solenoid in the form of waveform.
MODEL WORKING-
Required switch closed for 2sec. so as per requirement have given values in pulse generator. When the switch is closed then electromagnet/coil received the supply from battery. Strong magnetic field/flux produced in coil and pull the lever and create the mechanical force. This mechnical force sense by ideal translation motion sensor and gives output to the scope through PS to simulink convertor.
Observation-
As per given values in PG the output shown above. 0-2sec the output is null and 2-4sec it gives oscillation that means switch is closed for 2sec and producing the sound for 2sec.
Q2.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
ANS-
* In this model I have used the following blocks with the function.
1.Thermistor-
Thermistor is a temperature sensing element. Negative temperature coeficient using B parameter equation. When the temperature change difference can see inside the thermistor.
2. Controlled temperature source-
It is ideal energy source in thermal network. This block is used for maintain the temperature difference. The temperature difference is set by physical port S.
3. Signal builder-
The signal builder is use to create the signal in different waveform.
4. Battery-
It is use for DC supply.
5. Voltage sensor-
This block is represent an ideal voltage sensor device that convert voltage measured between any electrical connection into physical signal.
6. Resistor-
Resistor is used for load.
7. Switch-
The switch is used for the switching perpose only. The system block passes through the first input and third input based on the value of second input. If the input 2 is satisfied the value of selected criteria then switch is passed through the 1st input, otherwise pass through input 3 ( means if threashould value is greater than we given then switch passes to input1). The 1st and 3rd input are data ports and 2nd input is control port.
MODEL WORKING-
As per given question conditions created the signals from signal builder block. The block is shown above. So 1st converted all degree celcius value into kelvin for adding 273.15, then connect the constant block insted of signal builder and check the voltage of 25 degree celcius(25+273.15) in display. that value inserted as a threshould value in switch. Then again connect the signal builder and check the output from scope.
The output is shown below,
Observation-
The output shown as switch is ON when the temperature is greater than 25 degree celcius which is interval of 10-30sec. Again after 30sec switch is OFF at below 25 degree celcius of interval 30-50sec. that means fan is OFF.