esistance thermometers, also called resistance temperature detectors (RTDs), are sensors used to measure temperature. Many RTD elements consist of a length of fine wire wrapped around a ceramic or glass core but other constructions are also used. The RTD wire is a pure material, typically platinum, nickel, or copper. The material has an accurate resistance/temperature relationship which is used to provide an indication of temperature. As RTD elements are fragile, they are often housed in protective probes.
Resistance thermometers are constructed in a number of forms and offer greater stability, accuracy and repeatability in some cases than thermocouples. While thermocouples use the Seebeck effect to generate a voltage, resistance thermometers use electrical resistance and require a power source to operate. The resistance ideally varies nearly linearly with temperature per the Callendar–Van Dusen equation.
The platinum detecting wire needs to be kept free of contamination to remain stable. A platinum wire or film is supported on a former in such a way that it gets minimal differential expansion or other strains from its former, yet is reasonably resistant to vibration. RTD assemblies made from iron or copper are also used in some applications. Commercial platinum grades exhibit a temperature coefficient of resistance 0.00385/°C (0.385%/°C) (European Fundamental Interval).[7] The sensor is usually made to have a resistance of 100 Ω at 0 °C. This is defined in BS EN 60751:1996 (taken from IEC 60751:1995). The American Fundamental Interval is 0.00392/°C,[8] based on using a purer grade of platinum than the European standard. The American standard is from the Scientific Apparatus Manufacturers Association (SAMA), who are no longer in this standards field. As a result, the "American standard" is hardly the standard even in the US.
Lead-wire resistance can also be a factor; adopting three- and four-wire, instead of two-wire, connections can eliminate connection-lead resistance effects from measurements (see below); three-wire connection is sufficient for most purposes and is an almost universal industrial practice. Four-wire connections are used for the most precise applications.
We provide you Project Temperature Sensors – Types.You can choose the best of your choice and interest from the list of topics we suggested. All new project ideas that are appearing focuses to improve the knowledge of Engineering students.
https://www.elprocus.com
Visit our page to get more ideas on Project Report Format for Final Year Engineering Students these ideas developed by professionals.
Elprocus provides free verified electronic projects kits around the world with abstracts, circuit diagrams, and free electronic software. We provide guidance manual for Do It Yourself Kits (DIY) with the modules at best price along with free shipping.
Resistance Temperature Detector
WHAT IS RTD ?
WHY IS RTD USED?
Typical Design
RTD PROBE
Common Resistance materials for RTD
Advantages of RTD
Application OF RTD
Question and Answers
Usage of Platinum
esistance thermometers, also called resistance temperature detectors (RTDs), are sensors used to measure temperature. Many RTD elements consist of a length of fine wire wrapped around a ceramic or glass core but other constructions are also used. The RTD wire is a pure material, typically platinum, nickel, or copper. The material has an accurate resistance/temperature relationship which is used to provide an indication of temperature. As RTD elements are fragile, they are often housed in protective probes.
Resistance thermometers are constructed in a number of forms and offer greater stability, accuracy and repeatability in some cases than thermocouples. While thermocouples use the Seebeck effect to generate a voltage, resistance thermometers use electrical resistance and require a power source to operate. The resistance ideally varies nearly linearly with temperature per the Callendar–Van Dusen equation.
The platinum detecting wire needs to be kept free of contamination to remain stable. A platinum wire or film is supported on a former in such a way that it gets minimal differential expansion or other strains from its former, yet is reasonably resistant to vibration. RTD assemblies made from iron or copper are also used in some applications. Commercial platinum grades exhibit a temperature coefficient of resistance 0.00385/°C (0.385%/°C) (European Fundamental Interval).[7] The sensor is usually made to have a resistance of 100 Ω at 0 °C. This is defined in BS EN 60751:1996 (taken from IEC 60751:1995). The American Fundamental Interval is 0.00392/°C,[8] based on using a purer grade of platinum than the European standard. The American standard is from the Scientific Apparatus Manufacturers Association (SAMA), who are no longer in this standards field. As a result, the "American standard" is hardly the standard even in the US.
Lead-wire resistance can also be a factor; adopting three- and four-wire, instead of two-wire, connections can eliminate connection-lead resistance effects from measurements (see below); three-wire connection is sufficient for most purposes and is an almost universal industrial practice. Four-wire connections are used for the most precise applications.
We provide you Project Temperature Sensors – Types.You can choose the best of your choice and interest from the list of topics we suggested. All new project ideas that are appearing focuses to improve the knowledge of Engineering students.
https://www.elprocus.com
Visit our page to get more ideas on Project Report Format for Final Year Engineering Students these ideas developed by professionals.
Elprocus provides free verified electronic projects kits around the world with abstracts, circuit diagrams, and free electronic software. We provide guidance manual for Do It Yourself Kits (DIY) with the modules at best price along with free shipping.
Resistance Temperature Detector
WHAT IS RTD ?
WHY IS RTD USED?
Typical Design
RTD PROBE
Common Resistance materials for RTD
Advantages of RTD
Application OF RTD
Question and Answers
Usage of Platinum
Discussing what is temperature. How to calibrate a thermometer. Liquid in glass thermometers. Calibrate a liquid-in-glass thermometer using two fixed points. Characteristics of a quality/ good thermometer.
This Presentation can be used by the Students of Engineering who Deals with the Subject INDUSTRIAL INSTRUMENTATION and use it for Refrence (Anyways you Guys will Copy Paste or Download it) ;)
Introduction to Temperature Measurement and Calibration Presented by Fluke Ca...Transcat
Temperature is one of the most commonly measured physical parameters. This webinar will cover the best devices to use in temperature measurement and when to calibrate.
The thermocouple is a device which converts thermal energy to electrical energy. It is particularly used as a thermosensor. It has wider applications in instrumentation and measurements.
This PPT gathered many relevant topics relating to thermocouple like its working, principle, laws and different types.
Thank you!
Discussing what is temperature. How to calibrate a thermometer. Liquid in glass thermometers. Calibrate a liquid-in-glass thermometer using two fixed points. Characteristics of a quality/ good thermometer.
This Presentation can be used by the Students of Engineering who Deals with the Subject INDUSTRIAL INSTRUMENTATION and use it for Refrence (Anyways you Guys will Copy Paste or Download it) ;)
Introduction to Temperature Measurement and Calibration Presented by Fluke Ca...Transcat
Temperature is one of the most commonly measured physical parameters. This webinar will cover the best devices to use in temperature measurement and when to calibrate.
The thermocouple is a device which converts thermal energy to electrical energy. It is particularly used as a thermosensor. It has wider applications in instrumentation and measurements.
This PPT gathered many relevant topics relating to thermocouple like its working, principle, laws and different types.
Thank you!
The transformation of vitality starting with one frame then onto the next is known as Transduction. A transducer fills
for this need.
A transducer is a device which converts signals from one form to another. This can include loudspeakers and linear
positioned are well as physical quantity to electrical signal devices. The latter are most frequently referred to as sensors.
They allow computers and other electronic devices measure, operate and control things.
We can state that Every transducer is likewise (or has) a sensor yet every sensor requires not be a transducer.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
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TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
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COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
1. Temperature Measurement and
Control
• What is the definition of temperature?
– Correlates to molecular kinetic energy
– Measure of the “quality of heat”
• Reference material
http://www.omega.com/temperature/Z/zsection.asp
2. Temperature Measurement and
Control
•Applications for physicists
–Necessary for some other process of interest
•Purification by vacuum sublimation
•Device fabrication
•Crystal growth
•Cold traps for numerous applications
•Process needs to be done under predetermined thermal conditions
–Inherent to an experiment
•Measurement of temperature dependence of some property
•Determination of temperature at which some physical phenomenon
occurs
•Temperature dependence of experiment needs to be controlled with
high precision
3. Devices and Techniques for
Temperature Measurement
• Requires material parameter proportional
to temperature
• Uncertainty principle applies! How much
does the act of measuring the temperature
and getting the result out change the
system temperature?
• Under what circumstances is the act of
taking the measurement insignificant?
4. Devices for Temperature
Measurement
• Expansion thermometers
– Familiar
– Convenient
• Thermocouples
• RTDs (Resistive Temperature Devices)
• Thermistors
• Integrated Circuits
• Optical pyrometers
• Infrared thermometers
6. Non-Electronic Thermometry
• Expansion thermometers
– Common
– Inexpensive
– Absolute or differential
– Huge thermal mass
– Very slow to respond
• Bimetallic strip thermometers
– Dial
– Convenient
– Inexpensive
– Poor accuracy and precision
– Great for food preparation
7. Radiative Methods
• Optical pyrometer
– Body of interest must emit in the visible
– Ancient technology
– Temperature measured must be at least 650 C
– Essentially no upper limit to capability
• Infrared Thermometers
– “Quantum detectors”
• Basically solar cells in the IR
• Fit blackbody spectrum
– “Thermal detectors”
• Bolometers, pyroelectric detectors
• Radiation causes temperature of detector to rise
8. Thermal Expansion Coefficient
• Classic mercury-in-glass
• When are they useful?
• What are some applications?
• Why do they have the shape they do?
• Alcohol thermometers
– Why use them?
– (Hint: Tm(Hg) = 234.32 K = -38.84 C)
9.
10. • V(T) = V0(1
+ aT
+ bT2
+ cT3)
dV/dT = a +
2bT + 3cT2
0.81 < a <1.57x10-3
11. • Mercury
– a = 0.181690x10-3
– b = 0.00295x10-6
– C = 0.0115x10-8
Note: “Coefficient at
20 C” = a +bT + CT2
where T = 20
13. Thermocouples
• Seebeck Effect
– Any conductor subjected to a temperature
gradient generates a potential difference
– Measuring potential difference requires
attaching leads and a voltmeter
– Completing circuit means no net potential
difference around the circuit
– How to get useful information?
15. Thermocouple types
Type K (chromel–alumel) is the most common general
purpose thermocouple. It is inexpensive available in a
wide variety of probes. They are available in the −200 °C
to +1350 °C range. The type K was specified at a time
when metallurgy was less advanced than it is today and,
consequently, characteristics vary considerably between
examples. Another potential problem arises in some
situations since one of the constituent metals, nickel, is
magnetic. One characteristic of thermocouples made
with magnetic material is that they undergo a step
change when the magnetic material reaches its Curie
point. This occurs for this thermocouple at 354 °C.
Sensitivity is approximately 41 µV/°
16. Thermocouple types
• Type E (chromel–constantan)[4] has a high
output (68 µV/°C) which makes it well suited to
cryogenic use. Additionally, it is non-magnetic.
• Type J (iron–constantan) is less popular than
type K due to its limited range (−40 to +750 °C).
The Curie point of the iron (770 °C) causes an
abrupt change to the characteristic and it is this
that provides the upper temperature limit. Type J
thermocouples have a sensitivity of about
50 µV/°C.[3]
17. Thermocouple types
• B, R, and S
• Types B, R, and S thermocouples use platinum or a
platinum–rhodium alloy for each conductor. These are
among the most stable thermocouples, but have lower
sensitivity, approximately 10 µV/°C, than other types.
The high cost of these makes them unsuitable for
general use. Generally, type B, R, and S thermocouples
are used only for high temperature measurements.
• Type S thermocouples use a platinum–rhodium alloy
containing 10% rhodium for one conductor and pure
platinum for the other conductor. Like type R, type S
thermocouples are used up to 1600 °C. In particular,
type S is used as the standard of calibration for the
melting point of gold (1064.43 °C)
18. Thermocouple types
• Chromel-gold/iron
• In chromel-gold/iron thermocouples, the positive
wire is chromel and the negative wire is gold
with a small fraction (0.03–0.15 atom percent) of
iron. It can be used for cryogenic applications
(1.2–300 K and even up to 600 K). Both the
sensitivity and the temperature range depends
on the iron concentration. The sensitivity is
typically around 15 µV/K at low temperatures
and the lowest usable temperature varies
between 1.2 and 4.2 K
19. Resistive Temperature Detectors
• What is a platinum RTD?
• Basically nothing but a coil of very thin
platinum wire whose resistance is 100
ohms at room temperature
• R = R0(1 + AT + BT2) T > 0 C
– R0 = 100 ohms
– A = 3.9083 x 10-3 C-1
– B = -5.775 x 10-7 C-2
20. Resistive Temperature Detectors
• Why use an RTD instead of a thermocouple
or thermistor sensor?
Each type of temperature sensor has a particular
set of conditions for which it is best suited. RTDs
offer several advantages:
A wide temperature range (approximately
-200 to 850°C)
Good accuracy (better than thermocouples)
Good interchangeability
Long-term stability
21. RTD standards
• Two standards for platinum RTDs:
– European standard (also known as the DIN or IEC
standard)
– American standard.
• The European standard is considered the world-
wide standard for platinum RTDs.
-Requires the RTD to have an electrical
resistance of 100.00 Ω at 0°C
-Requires a temperature coefficient of
resistance (TCR) of 0.00385 Ω/Ω/°C
between 0 and 100°C.
• Two resistance tolerances specified
– Class A = ±(0.15 + 0.002*t)°C or 100.00 ±0.06 Ω at 0ºC
– Class B = ±(0.3 + 0.005*t)°C or 100.00 ±0.12 Ω at 0ºC
22. Thin Film
Thin-film RTD elements are produced by
depositing a thin layer of platinum onto a
substrate.
• A pattern is then created that provides an
electrical circuit that is trimmed to provide a
specific resistance.
• Lead wires are then attached and the element
coated to protect the platinum film and wire
connections.
23. Wire wound RTDs
• Two types of wire-wound elements:
– those with coils of wire packaged inside a ceramic or
glass tube (the most commonly used wire-wound
construction),
– those wound around a glass or ceramic core and
covered with additional glass or ceramic material
(used in more specialized applications).
24. Thermistors
• Thermistors differ from resistance
temperature detectors in that the material
used in a thermistor is generally a ceramic
or polymer, while RTDs use pure metals.
• The temperature response is also
different; RTDs are useful over larger
temperature ranges.
25. Steinhart-Hart Equation
• a, b and c are called the Steinhart-Hart
parameters, and must be specified for each
device.
• T is the temperature in Kelvin .
• R is the resistance in Ohms.
• The error in the Steinhart-Hart equation is
generally less than 0.02°C in the measurement
of temperature.
26. B Parameter Equation
• NTC thermistors can also be characterised
with the B parameter equation, which is
essentially the Steinhart Hart equation with
c=0
27. Thermistors
• Many NTC thermistors are made from a pressed
disc or cast chip of a semiconductor such as a
sintered metal oxide.
• Most PTC thermistors are of the "switching"
type, which means that their resistance rises
suddenly at a certain critical temperature. The
devices are made of a doped polycrystalline
ceramic containing barium titanate (BaTiO3) and
other compounds.
28. Self-heating in Thermistors
• Pin = IV = V2/R = I2R
• Pout = K(TR – Tamb) Newton’s Law of Cooling
• In thermal equilibrium Pin = Pout
• V2/R = K(TR – Tamb)
• TR = Tamb + V2/KR = Tamb + I2R/K
• Hence temperature read by device depends
on how much current you feed into it to read
its resistance.
• Uncertainty principle!
29. Terms Characterizing Thermistor
Performance
• DISSIPATION CONSTANT
The ratio, (expressed in milliwatts per
degree C) at a specified ambient
temperature, of a change in power
dissipation in a thermistor to the resultant
body temperature change.
• Why is this relevant?
• When is it important?
30. Terms Characterizing Thermistor
Performance
• THERMAL TIME CONSTANT
The time required for a thermistor to
change 63.2% of the total difference
between its initial and final body
temperature when subjected to a step
function change in temperature under
zero-power conditions.
• Why is this relevant?
• When is it important?
31. Terms Characterizing Thermistor
Performance
• RESISTANCE RATIO CHARACTERISTIC
The resistance ratio characteristic
identifies the ratio of the zero-power
resistance of a thermistor measured at
25°C to that resistance measured at
125°C
32. Thermistors: Applications
• Thermometry!
• PTC thermistors can be used as current-limiting
devices for circuit protection, as fuses.
• Current through the device causes a small
amount of resistive heating.
• If the current is large enough to generate more
heat than the device can lose to its
surroundings, the device heats up, causing its
resistance to increase, and therefore causing
even more heating. This positive feedback
drives the resistance upwards, reducing the
current and voltage available to the device.
33. Thermistors: Applications
• NTC thermistors are used as resistance
thermometers in low-temperature
measurements of the order of 10 K.
• NTC thermistors can be used as inrush-
current limiting devices in power supply
circuits.
34. 143-502LAG-RC1 NTC Thermistor
• Manufacturer: HONEYWELL S&C / FENWALL
• Newark Part Number: 30F1712
• Manufacturer Part No: 143-502LAG-RC1.
• RoHS Compliance : No
• Description
• NTC Thermistor
• Resistance: 5 kohm (at “room temperature”)
• Thermistor Tolerance: ± 10%
• Dissipation Constant: 7mW/°C
• Leaded Process Compatible: No
• Mounting Type: Through Hole
• Peak Reflow Compatible (260 C): No
• Resistance Ratio: 9
• RoHS Compliant: No
35. Temperature Control
(A Wholly Owned Subsidiary of “Process Control”)
• Why is this important?
• Good science requires that to correlate
cause and effect, all other parameters must
remain constant as only one parameter is
changed and another observed.
• “Process controls” are required to keep
parameters constant.
• “Process controls” also allow one parameter
to be changed in a defined, controlled
manner.
36. Terminology
• Controller (temperature): A device that
makes continuous operator attention and
input unnecessary.
• Examples
– Cruise control on car
– Fill valve in your toilet tank
– Thermostat in your house
• This is an example of one simple type of
temperature controller: “On-off”
• Contrast with “temperature controller” on your [gas]
barbeque!
37. Terminology
• Set Point: the desired temperature that
you want in your system
• Error: difference between set point and
actual temperature in your system
– Error = Set Point - Measurement
38. Specific Example
• You want to control the temperature of a
furnace.
• n.b.: you actually control the current fed
into the heating coils or windings
• Example works for any general process
control with feedback
39. PID Control
• P = Proportional
– Power output is proportional to error signal
= 100/Gain
Gain? Gain = ratio of output change to error
• I = Integral
– If output is proportional to error, what is output when
there is no error?
– Corrects for “droop”
– Also known as reset
– Basically an offset to confuse the controller
• D = Derivative
– Related to slope of error signal
– Also known as rate
40. PID Control
• Proportional band: Size of error within
which output is proportional to error signal
– If signal is below proportional band, supply
gives full output
– If signal is above proportional band, supply
shuts off completely
– If proportional band is too wide, control is poor
– If proportional band is too narrow, system will
oscillate
– Various schemes for proportioning power
input to furnace
42. Adjusting PID Parameters
• http://www.omega.com/temperature/Z/pdf/z115-117.pdf
• http://www.expertune.com/tutor.html
• Old-fashioned
– plot TC output on a chart recorder.
– Balance TC approximate output with precisely adjusted voltage
– Observe change in system temperature when set point has
changed
• Modern old-fashioned
– Use $130 Omega A/D converter to enter TC data into computer
• Truly modern solution
– But auto-tuning controller