SIMULINK MODEL FOR DOOR-BELL & THERMISTOR CONTROLLED FAN
MODELLING OF DOORBELL USING SOLENOID BLOCK
AIM:
To Make a Simulink model of Doorbell using solenoid block
OBJECTIVE:
- Analyze the physical movement of the plunger by creating a situation where the switch is closed for 2 seconds and then released.
INTRODUCTION:
MECHANISM OF DOOR BELL:
An electric bell has an electromagnet that pulls a strip of iron which makes the plunger hit the gong to ring the bell and makes sound. A solenoid is just an electromagnet where the coiled wire surrounds a metal strip. The strip contains magnetically conductive metal, so it can be moved backward or forward by the electromagnetic field.
In many instances, the solenoid piston consists of an iron core mounted to a non-magnetic metal bar. When there is no power to the electromagnet, a spring pushes the piston to the left, and the iron core extends outside of the wire coil. When you turn the electromagnet on (by pressing the doorbell button), the iron core is drawn to the magnetic field, so it slides into the center of the coiled wire. Current will flow through the electromagnet and the piston will remain in this position.
THE BLOCKS USED IN SIMULATION AND EXPLANATIONS:
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. By differing the Amplitude, Pulse Width, Period, and Phase delay the different square wave pulses are generated. In time-based mode, it computes the block output only at times when the output actually changes. This approach results in fewer computations for the block output over the simulation time period.
In order to observe the physical movement of the plunger, the switch is closed for 2 seconds and then released. For that the delay time assigned as 2 seconds. The period and pulse width is assigned based on the time intervals and the simulation time is assigned as 10 seconds.
Simulink to PS converter - The simulink signals are converted into physical signals by using Simulink -PS converter. Then the signals are connected to switch system
Switch - The Switch block models a switch controlled by an external physical signal. The generated pulse signlas are converted and connected to switch block. If the external physical signal PS is greater than the value specified in the Threshold parameter, then the switch is closed, otherwise the switch is open.
Battery - The switch is then connected to the battery, when the switch is closed the electromagnet receives electrical power from the battery.
Solver Configuration - The Solver Configuration block specifies the solver parameters that the model needs before begin simulation. Each topologically distinct Simscape block diagram requires exactly one Solver Configuration block to be connected to it.
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.
Solenoid - The solenoid block acts as a Electro-mechanical device in which the electrical signals are been converted into an equivalent mechanical signal.
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.
Mechanical Referance - 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.
PS to Simulink Converter - Convert physical signal into Simulink output signal. The damped signal from the motion sensor are then converted into simulink signal which shows the plunger position of door bell through scope.
Scope - Scope block display time domain signals, the scope displays simulation results for attached input signals. From the output of delay signal to 2 seconds the plunger positions are been obsorved.
MODELLING OF DOOR BELL:
OUTPUT:
The simulation time to be assigned as 10 seconds. From that the equations from the blocks are computed, signals and states are solved and updated in the scope where the position of plunger are determined. The pulse are generated wit the delay time of 2 seconds then the signals are converted into physical signals and connected to switch block. In the switch block if the thresold value is statis fied the switch turns on and the electrical flow takes place.
The solenoid block act as a electro mechanial device in which the signals are been monitered by ideal translational motion sensor. Then the signals are converted into simulink signal to visualize the damped plunger position.
LINK OF MODEL:
- https://drive.google.com/file/d/1mMbgwowW90AjSHX9fbdC-8hXZj8VUVop/view?usp=sharing (NEW VERSION)
- https://drive.google.com/file/d/17bWuh39dct42_XuSGG-PZo2w148j4yZZ/view?usp=sharing (OLD VERSION- ELECTRICAL NOT SIMULATED IN OLDER VERSIONS)
MODELLING OF THERMISTOR CONTROLLED FAN
AIM:
To Make a Simulink model of a thermistor to sense the temperature of a heater to turn on or turn off a fan.
OBJECTIVE:
- Use a thermistor to sense the temperature of a heater
- Based on the input conditions to turn on or turn off the fan by creating the desired input signal.
INTRODUCTION:
THERMISTOR:
The Thermistor is a temperature sensor that works on the principle of varying resistance with temperature. They are made of semiconducting materials. A thermistor is made of oxides of metals such as Nickel, Manganese, Cobalt, Copper, Uranium etc. It is available in a variety of shapes and sizes. Commonly used for configurations are Disk type, Bead type and Rod type.
There are two types of thermistors:
(1). Negative Temperature Coefficient (NTC)
(2). Positive Temperature Coefficient (PTC).
An NTC thermistor, when the temperature increases, resistance decreases. Conversely, when temperature decreases, resistance increases. This type of thermistor is used the most.
A PTC thermistor works a little differently. When temperature increases, the resistance increases, and when temperature decreases, resistance decreases. This type of thermistor is generally used as a fuse.
THE BLOCKS USED IN SIMULATION AND EXPLANATIONS:
SIGNAL BUILDER - The Signal Builder block allows to create interchangeable groups of piecewise linear signal sources and use them in a model. In the Signal Builder window, create signals and define the output waveforms.
The signals are created based on the input conditions;
- 0 to 10 sec - 20 deg C (293.15 K)
- 10 to 30 sec - 27 deg C (300.15 k)
- 30 to 50 sec - 23 deg C (296.15 k)
The time rage of the signals are assigned from 0 to 50 seconds and the signals are builded based on the temperature ranges.
Simulink to PS converter - The simulink signals are converted into physical signals by using Simulink -PS converter. Then the signals are connected to controlled temperature source.
Controlled Temperature Source - The Controlled Temperature Source block represents an ideal source of thermal energy that is powerful enough to maintain specified temperature difference across the source regardless of the heat flow consumed by the system. Connections A and B are thermal 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. The builded signal are converted and connected to controlled temperature source block. The temperature differential across the source is directly proportional to the signal at the control port S.
THERMISTOR - Negative Temperature Coefficient (NTC) thermistor using B-parameter equation are used to pass the geenrated controlled signals into an thermistor, where the thermistor senss the temperature of the heater and passes the signal based on desired conditions.
Solver Configuration - The Solver Configuration block specifies the solver parameters that the model needs before begin simulation. Each topologically distinct Simscape block diagram requires exactly one Solver Configuration block to be connected to it.
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.
Resistor -The Linear resistor in electrical systems are connected to the ideal voltage sensor to determine the flow of current through the circuit.
Battery - The terminals of battery connected to the sensors and thermistor block to flow the current through te circuit and the desired voltage ranges are identified using voltage sensor.
Voltage Sensor - The Voltage Sensor block represents an ideal voltage sensor, that is, a device that converts voltage measured between two points of an electrical circuit into a physical signal proportional to the voltage. Connections + and – are electrical conserving ports through which the sensor is connected to the circuit. Connection V is a physical signal port that outputs the measurement result.
PS to Simulink Converter - Convert physical signal into Simulink output signal. The measured voltage range values are identified for 25 deg C. In order to turn the fan on, the regulated voltage value are been determined when the voltage are increased as per the input conditions.
Display - The converted signals are connected to display, inorder to identify the treshold value of the temperature @ 25 deg c. The thresold value is used as a control parameter in switch block.
Scope - Scope block display time domain signals, the scope displays simulation results for attached input signals.The resulted output voltage range are determined for 25 deg c.
Switch - The Switch block passes through the first input or the third input signal based on the value of the second input. The first and third inputs are data input. The second input is a control input. Specify the condition under which the block passes the first input by using the Criteria for passing first input and Threshold parameters. The threshold value are noted and the values are assigned as 0.01099. If the threshold value are statisfied the signals then passes through the controlled voltage sorces.
Controlled Voltage Source - The Controlled Voltage Source block represents an ideal voltage source that is powerful enough to maintain the specified voltage at its output regardless of the current flowing through the source. The thershold is statisfied the signals are converted into simulink to physical signals and passes through it.
DC Motor - DC motor model with electrical and torque characteristics and fault modeling. In which the elcetrical signals are transferred into motor to run and the electrical signals are converted to mechanical signals whic are been moniterd by ideal rotational motion sensor.
Ideal Rotational Motion Sensor - The Ideal Rotational Motion Sensor block represents an ideal mechanical rotational motion sensor, that is, a device that converts an across variable measured between two mechanical rotational nodes into a control signal proportional to angular velocity or angle. Connections R and C are mechanical rotational conserving ports that connect the block to the nodes whose motion is being monitored. Connections W and A are physical signal output ports for velocity and angular displacement, respectively.
Goto - The Goto block passes its input to its corresponding From blocks. The input can be a real- or complex-valued signal or vector of any data type. From and Goto blocks allow you to pass a signal from one block to another without actually connecting them.
From - The From block accepts a signal from a corresponding Goto block, then passes it as output. The data type of the output is the same as that of the input from the Goto block. From and Goto blocks allow you to pass a signal from one block to another without actually connecting them.
MODELLING OF THERMISTOR CONTROLLED FAN:
The Thermistor controlled fan model are designed with three subsystems. Input signal where the signals are builded based on input conditions. Switch system is operated based on thershold value. Electro mechanical system where the signals are statsified as input conditions.
INPUT SIGNAL:
In the subsystem 1 the signal builder is used to build the input signal based on the input consitions.Then the signals are converted to physical signal and connected wit controlled temperature source. The output of the signal is visulazed using goto bolck. From the respective FROM block the signals are retrived. The controlled temperature signals are passed to thermistor.
SWITCH SYSTEM:
In the subsystem 2 the switches conditions are used. The two constant blocks are used to provide the consatnt values and at port 2 the thershold value are assigned at 25 deg c. From the voltage sensor the thresold value are monitered. From the threshold value if it statisfies the repspected time intervel(@ 10 - 30 sec) and @ 25 deg c the fan is in ON condition otherwise it will be turn OFF.
The subsystem 2 is masked and prompt was taken to inputting the desired Thershold value at desired temperature. The masking is used to assign the parameter values in the easiest manner. Here the Thershold values are assigned at 25 des c.
ELECTRO - MECHANICAL SYSTEM:
In subsystem 3 the conditioned signals are converted and passed through controlled voltage source.
From which the DC motor actuated based on the threshold value (Voltage). Based on the Voltage rise @ 10 sec the fan is in ON condition till 30 sec. Then the fan is in OFF condition. The measured motor speed is noted as 1454rad/s.
THERMISTOR CONTROLLED FAN:
OUTPUT:
The result of input signal , voltage signal and Angular velocity, angle are portrayed. From the it is obsorved that at 10 - 30 seconds the fan is in ON condition in other state that is from 0-10 seconds and 30-50 seconds the fan is in OFF condition.
LINK OF THE MODEL:
- https://drive.google.com/file/d/1V6mnJtKZYF2M3_FQWa-UPRrwgERFuIMJ/view?usp=sharing (NEW VERSION)
- https://drive.google.com/file/d/1GWCFbyQmAhf8e3L5nJ5ZETsj2ksrSccv/view?usp=sharing (OLDER VERSION- ELECTRICALS NOT SIMULATED)
ERRORS WHILE SIMULATION:
- In PS-Simulink converter error occured
STEPS TO OVERCOME THOSE ERRORS:
- Inuput Handling, filters are assigned
CONCUSION:
- The Plunger physical movement is obsorved when the switch is closed for 2 seconds and then released.
- Based on the input conditions signals are created
- Heater temperature is sensed using thermistor and based on the condition threshold values are identifird
- As on output condition, using DC motor the fan is ON at 10-30 sec time intervel. Above 25 deg C.
REFERENCE: