Simulink Model of Thermistor to sense the temperature of a heater & trigger a fan.
Aim:
Create a simulink model of thermistor to sense the temperature of a heater & turn on or turn off the fan.
Conditions:
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.
Blocks used in model:
- Repeating Sequence Stair
- Controlled Temperature Source
- Thermistor
- Resistor
- Voltage sensor
- Battery
- Switch
- Lamp
- Scope
- Dsiplay
- PS-Simulink Converter
- Simulink-PS Converter
- Solver Configuration
Simulink Model:
Model Explanation:
A Repeating Sequence Stair is given as input to the thermistor through a controlled temperature source. The definition of Repeating Sequence Stair block is given below.
The conditions of the temperature source is defined inside the above window. The sample time was taken as 10s and the whole simulation time was taken as 50s.
Battery and a resistor is connected in the thermistor circuit. A voltage sensor was given accross this resistor to measure the voltage change during different temperature inputs. The resistance of this resistor can be set to any value, but it should not be changed once the threshold voltage is found. The threshold temperature was given as 25 degree Celsius and the corresponding voltage over the resistor was found out, through a display connected to the voltage sensor. At this time the Repeating Sequence Stair was given only one value, i.e, 25 degree Celsius or 298 K. The output from the voltage was also given into a switch which is linked to a lamp which displays different colours based on the logical conditions. The lamp color was set to red if the temperature was below 298K and to green when the temperature is above 298K.
Results:
When the temperature is above 298K
When the temperature is below 298K