Week -2

AIM:

1. To make a simulink model od doorbell using solenoid block.
2. To use a thermistor to sense the temperature of a heater and turn on or off the fun

OBJECTIVE:

1. To create a situation where the switch is closed for 2sec and then released.observe the physical movement of the plunger.
2. To sense the temperature of a heater by using some condition are give below

• Temperature source: 20℃ from 0 to 10sec, 27℃ from 10 to 30sec 23℃ from 30 to 50sec.
• Fan condition: ON if the temprature above 25℃, OFF

In this model,i used the following blocks with their functiond:

1. solenoid
2. battery
3. switch
4. pulse generator
5. ideal translational motion sensor

• solenoid -electrical energy into kinetic energy. The solenoid block represents the electrical characteristics and genareted force.
• Buttary-gives supply for the solenoid.
• switch- to complete the connection.
• pulse generator- the pulse generator block genarates squre wave pulse at regular intervels pulse generated from PG is converted to simulink to physical signal and given to switch for perform switch function.

following are the valuse for the PG :ampitude:1,pulse width:20,period:10sec,phase delay:2.

• Ideal translational motion sensor-physical movement done by the solenoide is sensed by the ideal translational motion sensor.
• fundamental blocks for output and electrical,mechanical references.

Model explanation:

1. The pulse generator is used to give the signal input where ,amplitude=1, period=10sec,pulse width=20 and phase delay=2sec.
2. from the use of " Simulink -ps converter"and futher send to the switch for the electrical circuit.
3. The electrical circuit consists of a solenoid, a buttary and a switch one end of the solenoid is connected to the battery and its other end is connected to the switch. an electrical reference is provided in the electrical circuit.
4. The mechanical part of the solenoid is connected to an ideal translation motion sensor and mechanical translation reference.
5. the p-port of the sensor make a connection with the "PS-simulink covertor" to provide the output in signal from.Futher, the convertor is connected with the scope to display our output signal.
6. A solver configuration is connected to an electrical circuit to solve all parameters before the begginning of the simulaton.

THERMISTOR:

Simulink model explanation

• controlled tempurature source - The controlled tempurature source block represents an ideal source of thermal energy that is powerfull enough to maintain the specificed tempurature difference across the source redardless of the heat flow consumed by the system.

connections A and B are themal conserving ports corresponding to the source inlet and outlet,respectively port S is a physical signal port ,through which the control signal that drives the source is applied

• Thermistor- A thermistor is a type of resistor whose resistance is depandent on the tempurature ,more so then is standard resistor. the word is a combination of the thermal and resistor.the thermistor block represents an NTC thermistor using the B -paremeter equation.

NTC-negitive temperature co-efficient

• resistor- The resistor block models a linear resistor , described with the following equation.

v= I.R

where ,

V= voltage

I= current

R= resistor

• Voltage sensor- The voltage sensor block represent an ideal voltage sensor ,that is, a device that convert voltage measured between two points of an electrical circuit into physical signal proportional to the voltage.
• Voltage source-The voltage source block implements a voltage source with DC, AC AND noisce components
• electrical reference- The electrical reference block represents an electrical ground. electrical conserving ports of all the blocks that are directly connected to ground must be connected to an electrical reference block.

PROCEDURE-

1. First i build the signal from the signal bulider and provide the input as per given criteria.

At point 1, time =0 to 10 seconds,temperature=293k

At point 2, time = 10 to 30 seconds,temperature=300k

At point 3,time =30 to 50 seconds,temperature=296k

2.Now the signal are passed from simulink-PS convertor to the controlled temprature source where these are further connected to the thermistor.

3.Thermistor are aheard connected to battary terminal and to the resistor which is attached to the voltage sensor.

4.Voltage sensor is provide to sense the voltage of current which is placed across the resistor.

5. A thtreshold value of voltage is provided corresponding of the temperature 25℃. if the value is above that current flows through it and graph are produced.
6. If a value is geater than threshold value it show '1' otherwise '0'.

For 0 to 10s fan is OFF condition because temperature is 293k which is below the threshold 298k.after 10s temperature goes to 300k then the switch will be in ON condition as the temperature exceeds 298k.after 30s fan will turn OFF as the temperature comes down to 296k which ia below the threshold temperature of 298k.

From the above conditions,all the values are evaluated.