Week -2
1) Simulink model of Doorbell using solenoid block:::
>> The heart of a doorbell is an electromagnet. When you press a doorbell button, you complete an electrical circuit that allows household electricity to flow through the doorbell's internal electromagnet. The magnetic field generated by the electromagnet is then used to power a mechanism that creates the doorbell sound.
>> SIMULINK BLOCKS USED;;
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)scope- used for the plot visible purpose of the model.here three scopes are used where as
- Time plot
- velocity plot
- position plot
3) simulink to ps converter- Converts the Simulink input signal to a Physical Signal.here used for different plot purposes.
4) SPST Switch- (single oloe single throw switch) is an ON/OFF control switch.
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When the switch is open, port p is connected to port n through a resistance with value equal to the reciprocal of the Open conductance parameter value.
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When the switch is closed, port p is connected to port n through a resistance with value equal to the Closed resistance parameter value.
5) Battery- is an power source used for power supply to the system.
6) mechanical and electrical references- represents a mechanical and electrical translational reference points, that is, a frame or a ground. Use it to connect mechanical and electrical translational ports that are rigidly affixed to the frame (ground).
7)Solenoid:: The Solenoid block represents the electrical characteristics and generated force for the solenoid
>This block implements the electrical and mechanical characteristics of a solenoid. Parameterization is in terms of two points [X1,F1] and [X2,F2] on its force-stroke curve for a 100 percent duty cycle at Rated voltage Vdc and Rated current Idc where X2>X1>0 are stroke values and F1>F2>0 are corresponding forces.
> The plunger fully in (i.e. air gap closed) corresponds to X=0, and pull-in force is assumed to decrease quadratically with the magnitude of X. To ensure the force remains finite, the following condition should hold: X2/X1>sqrt(F1/F2).
8) Ideal translational motion sensor:: measures velocity or displacement in a mechanical translational network. The sensor Bis ideal since it does not account for inertia, friction, delays, energy consumption.
9) slover configuration:: defines solver settings to use for simulation.
>>> BLOCK DIAGRAM::
>> PROCESS::
(1) The pulse generator generates the input signals for every 2sec duration to control the bell switch ringing.signals which are generated are plotted in scope and by using simulator-ps converts into real time values.
(2)Based on the signals generated the switch acts and current flow to the solenoid from the battery.when it passes through the solenoid generates the magnetic field to attract the armature.then the ideal motion sensor activates and conversts to the simulink phase and records the motions of the hammers acts.
>>> OUTPUT PLOTS:
1)Time:
2)velocity:
3)position:
2)Thermistor Simulation to sense the temperature of a heater & turn on off the fan
Thermistor:: The thermistor works on the simple principle of change in resistance due to a change in temperature. When the ambient temperature changes the thermistor starts self-heating its elements. its resistance value is changed with respect to this change in temperature. This change depends on the type of thermistor used.
>>BLOCKS REQUIRED::
1) Signal builder: The Signal Builder block allows you to create interchangeable groups of piecewise linear signal sources and use them in a model. You can quickly switch the signal groups into and out of a model to facilitate testing. In the Signal Builder window, create signals and define the output waveforms.
2)scope: uses for the plots displaying
3)simulink-ps convertor: Converts the Simulink input signal to a Physical Signal
4)solver configuration: defines solver settings to use for simulation.
5) Thermal reference: represents a reference point in a thermal network where the temperature is equal to absolute zero.
6)controlled temperature source: represents an ideal energy source in a thermal network that can maintain a controlled temperature difference regardless of the heat flow rate.
7)Thermistor: an NTC thermistor using the B-parameter equation.
>The resistance at temperature T is given by R(T) = R0*exp(B*(1/T-1/T0))
where R0 is the Nominal resistance at the reference temperature T0, and B is the Characteristic temperature constant.
>The temperature T of the thermistor is governed by the equation m*c*dT/dt = Q
where Q is the net heat flow into port A, m is the mass and c is the lumped specific heat capacity.
>The thermal mass m*c is calculated from the Thermal time constant t_c and the Dissipation factor K_d using the
equation m*c = K_d*t_c.
8)voltage sourec: an ideal voltage sensor, that is, a device that converts voltage measured between any electrical connections into a physical signal proportional to the voltage.
9)Resistor: resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines.
>The voltage-current (V-I) relationship for a linear resistor is V=I*R, where R is the constant resistance in ohms.
10) Battery: uses for the power supply to system and multiple batteries can be used based on requriments.
11)Switch: uses for the control of power supply in on/off conditions,here given an temp=25 set condition.
12)constant: getting output at requried conditions.
13)DC motor: assumes that no electromagnetic energy is lost, and hence the back-emf and torque constants have the same numerical value when in SI units.
>Motor parameters can either be specified directly, or derived from no-load speed and stall torque. If no information is available on armature inductance, this parameter can be set to some small non-zero value.
14)Ideal rotational motion sensor: measures angular velocity or angle in a mechanical rotational network. The sensor is ideal since it does not account for inertia, friction, delays, energy consumption.
15)ps-simulink converter: converts the input Physical Signal to a Simulink output signal.
16) Electrical and mechanical references: an electrical and mechanical rotational reference point, that is, a frame or a ground. Use it to connect mechanical and electrical rotational ports that are rigidly affixed to the frame (ground).
>> SIMULINK BLOCK DIAGRAM:::
>>>PROCESS::
>> CONDITIONS Required::
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
>> Input signal::
(1) The signal builder generates the signal as per requirmenst as show in the above plot.After these signal are passes through simulink-ps converter where inputs into physical inputs to the system.After passes through controlled temp source to thermistor.where temp conditions are adjusted as per given.
(2) In thermistor the signals are sensed and generates to the resistor,here after the voltage source is connected through thermistor and resistor and power supply battery.In the voltage the voltage is sensed and measures by voltmeter.The resistor uses where R varies w.r.t to the current(i),voltage . V=IR
(3)The voltage output is givn as input to the switch provided by on/off supply.when switch ON's the motor fan on's with an threshold value.Then after DC motor ON's at T=27 deg limit respectively,by using ideal rotational motion sebsor the movements of DC motor records and viewed in the scope provided.
>>OUTPUT PLOTS:::
1)Time:
2)velocity:
3)switch:
4)displacement:
