Week -2

1.ANSWER

The figure above is the representation of "A doorbell operated on solenoid". In this model, some blocks are used to make the working model of the doorbell. These blocks are:

1. Pulse Generator: The Pulse Generator block generates square wave pulses at regular intervals. The block waveform parameters, Amplitude, Pulse Width, Period, and Phase delay, determine the shape of the output waveform.

2. Simulink-PS Converter: Converts the unitless Simulink input signal to a Physical Signal.

3. Scope: Display signals generated during simulation.

4. Switch: Switch controlled by an external physical signal.

5. Battery: The Battery block represents a simple battery model.

6. Solenoid: Model electrical characteristics and generated force of solenoid.

7. Ideal Translational Motion Sensor: The Ideal Translational Motion Sensor block represents a device that converts an across variable measured between two mechanical translational nodes into a control signal proportional to velocity or position. You can specify the initial position (offset) as a block parameter. The sensor is ideal since it does not account for inertia, friction, delays, energy consumption, and so on.

8. Mechanical Translational Reference: The Mechanical Translational Reference block represents a reference point, or frame, for all mechanical translational ports. All translational ports that are rigidly clamped to the frame (ground) must be connected to a Mechanical Translational Reference block.

9. Electrical Reference: The Electrical Reference block represents an electrical ground. Electrical conserving ports of all the blocks that are directly connected to the ground must be connected to an Electrical Reference block. A model with electrical elements must contain at least one Electrical Reference block.

10. Solver Configuration: The Solver Configuration block specifies the solver parameters that your model needs before you can begin the simulation.

11. PS-Simulink Converter: Convert physical signal into Simulink output signal.

2.ANSWER

This figure shows the representation of thermistor connection which senses the temperature of a heater and passes the signal to a switch where a threshold limit is already set. If the temperature is above or equal to the threshold limit, then it gives "1" as output which is "Switch On". If the temperature is below the threshold limit, then it will give "0" as output which means "Switch Off". The input signal is generated with the help of a "Signal Builder" block (See Fig 9). This signal is created according to the conditions given in this challenge. The conditions are as following:

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.

Here the temperature is converted in Kelvin from degree Celcius because the signal converter does not take °C value as input. I also have to set the signal unit as "Kelvin" in Simulink-PS Converter.

The formula for conversion: 1 °C= 273.15 K

The Signal 1 is:

From 0-10 sec- Temperature is 293.15 K

From 10-30 sec- Temperature is 300.15 K

From 30-50 sec- Temperature is 296.15 K

Output:

It can be seen that the value of the signal is "0" from 0-10 sec because in this time the temperature was 20°C which is below 25°C means "Switch off the fan". After that, the signal value gives "1" as output from 10-30 sec because in this time the temperature was 27°C which is above 25°C means "Switch on the fan". The value of the signal is again goes to "0" from 30-50 sec because in this time the temperature was 23°C which is below 25°C means "Switch off the fan".

Now it is clear that our model is correct and fulfills all the input conditions.