Week -2

Aim:-

1. To make simulink model using solenoid block.
2. To use a thermistor to sense the temprature of a heater and turn on or turn off the fan.

1. Door Bell:-

Parameters:-

Amplitude = 1

Period = 4

Pulse Width = 50

Phase Delay = 2

Explanation:-

1. Pulse Generator
2. Switch
3. Battery
4. Solenoid
5. Ideal Translational motor sensor
6. Mechanical Translational Referance
7. Electrical Reference
8. Scope

As per the given conditions, switch is closed for 2 seconds and then released.

The pulse generator is used to create square wave pulses at regular inervals. The block waveform parameters, amplitude, Pulse width, period and phase delay, determine shape of the waveform.

Switch block is controlled by external physical signal and if the external signal is greater than the switch is closed or else switch is open.

Positive terminal is connected to block while as, the negative terminal is connected to the electrical reference. When we connect solenoid block eith the switch and battery we form a complete electrical circuit.

The port c is connected with the meachanical referance. The ideal translational sensor is connected with the solenoid block.

The signal from the pulse generator was converted using Simulink PS converter and is given to the input switch. A solenoid is introduced and battery is connected to it.

The position of the solenoid plunger is measured using an ideal translational motion sensor connected to the circuit.The spring constant and the damping parameters of the solenoid block was altered to obtain the desired graph.

The simulation was run for 20 seconds and the results obtained is shown above. It can be observed that the bell rang once per 2 seconds.

Thermistor:-

Thermistor is a device which measures temprature and its working is based on the relationship between resistance and temprature.

Given inputs:-

Temprature source: 20 degree celcius from 0 to 10 seconds, 27 degrees from 10 to 30 seconds and 23 degrees from 30 to 50 seconds.

Fan conditions: ON if the temprature is above 25 degree celcius, OFF otherwise.

Simulink Model:-

Simulink building block is added to input the values as per given conditions:-

1. At point 1,time = 0 sec to 10 sec and Temprature = 293K
2. At point 2,time = 10 sec to 30 sec and Temprature = 300K
3. At point 3,time = 30 sec to 50 sec and Temprature = 296K

• Controlled temprature source represents an ideal source of thermal energy, that can maintain a controlled temprature diffrence regardless of the heat flow rate.
• Thermistor is the type of resistor whose resistance is based upon temprature.
• A linear resistor 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 Configuration:Each physical network is represented by a connected simscape blocks requires solver settings information for simulation.

Result Thermistor:-

Fan is in OFF condition from 0 to 10 seconds as the temprature is below 293K which is below the threshold 298K. After 10 seconds the switch will be on as the temprature rises to 300K and exceeds the threshold of 298K. After 30 seconds the fan will be in OFF condition as the temprature comes down 296K which is below the threshold temprature of 298K.

All the values are evaluated using the above conditions.