Week -2

Q. 1. Make a Simulink model of Doorbell using solenoid block with the following details:

Ans:

Simulink Model:

• This model required a pulse signal for ringing the bell for 2 sec. So I created pulse signal with the help of ‘Pulse Generator’ block and its parameters are Amplitude: 1, Period: 4sec., Pulse width: 50% of period and Phase delay: 2sec.
• After this create a block diagram as per the above figure with help of Battery, Electric switch, Solenoid and Ideal Translational Motion Sensor. Also connect Electrical and Mechanical Translational references with respective element blocks. Solver Configuration connects for solving equations of simscape physical networks.
• Also connect Scope, Display for results and PS-simulink converter for converting simscape physical model into the simulink model.
• After all connections run the simulation with 10 sec stop time.

Result:

• Below shows the graph of Plunger Velocity, Plunger Position and Input of pulse generator.
• In the Pulse generator graph shows signal gives to the switch after every 2sec. And the switch is turn ON after the 2 sec switch get closed.
• Also in plunger velocity and position fluctuate after every 2sec.

Q. 2. Use a thermistor to sense the temperature of a heater & turn on or turn off the fan as per below conditions:

Input - 0 to 10 sec temp is 20 °C Output - Fan should be ON only

10 to 30-sec temp is 27 °C > 25° else OFF

30 to 50-sec temp is 23 °C

Ans:

Model:

• This model is built for turn ON and OFF the fan as per the conditions. So for these conditions the signal is created by the signal builder.Signal Builder signal shows in below figure.
• Block diagram draw as per shown in above figure. Before the signal builder, signal gives to controlled temperature source block gives input the 298 kelvin i.e. 25°C through a constant block for calculating the threshold voltage of the resistor which is connected in the block diagram as a load.
• After calculating the threshold voltage gives the signal builder signal to the controlled temperature source for creating temperature as per our condition and passes to the NTC thermistor.
• Also at the same time I used a switch for controlling the turn ON and OFF signal of the fan. For these switch gives a threshold value which I calculated earlier i.e. 0.03487 for 25°C.
• Now run the simulation with 50sec stop time after completing the block diagram.

Signal Builder Model:

Result:

• In the result graph shows Signal Builder signal, Switch ON-OFF Signal and Voltage across the resistor.
• As per our condition switch signal ON when temperature goes above the 25°C, otherwise signal is OFF.