Temp measurement

Powerpoint Templates Page 1

Characterization & Optimization of Temperature

Sensor Using LABVIEW

Completed By :

Shabnam Niknezhad

Samreen Shaikh

Guide :

Prof. SAJID NAEEM

MSc Electronic ScienceDepartment of Electronic SciencePoona College of Arts , Science & Commerce

http://www.powerpointstyles.com/


AIM & OBJECTIVESAim : • To study of LabVIEW and its application.

Objectives :• Characterization and Optimization of temperature sensors.• To interface DAQ card with LabVIEW.• To design ON/OFF controller to control Heater.• To develop basic programming architectures.• To develop Lab VIEW software for data acquisition, display

and/or control purpose.• To create application that use plug in DAQ device• To develop necessary interface hard ware so as to accumulate

variety of test and measurement procedure.• To study different transducers under the control of virtual lab.



INTRODUCTION• The primary objective of process control is to control physical

parameter such as temperature, pressure, flow rate, level, force, light intensity and so on. As these parameter can change either spontaneously or because of external influences, we must constantly provide corrective action to keep these parameters constant or within the specified range.

• To control process parameter, we must know the value of that parameter and hence it is necessary to measure that parameter.



• An instrumentation system consists of three major elements :

1. input device2. signal conditioning circuit 3. output device. The input quantity for most instrumentation system is non electrical in order to use electrical methods and techniques for measurement the non electrical quantity is converted into proportional electrical signal by a device

called “transducer”.



Transducer• A transducer is a device that converts one form of energy to another. Energy types include electrical, mechanical, electromagnetic (including light), chemical, acoustic or thermal energy. • While the term transducer commonly implies the use of a sensor/detector,

any device which converts energy can be considered a transducer. • Transducers are widely used in measuring instruments.

Bioelectrical TechnologyAt the heart of this system a wireless microelectromechanical system (MEMS) sensor in the contact lens that acts as a transducer, antenna, and mechanical support for read-out electronics.



Temperature sensor - overview

• In many systems, temperature control is fundamental. There are a number of passive and active temperature sensors that can be used to measure system temperature, including:

1. thermocouple,2. resistive temperature detector,3. thermistor, 4. silicon temperature sensors.

• These sensors provide temperature feedback to the system controller to make decisions such as, over-temperature shutdown, turn-on/off cooling fan, temperature compensation or general purpose temperature monitor.



Common Methods of Interfacing a Sensor



Block Diagram

LABVIEW

SIGNAL CONDITIONING

DATA AQUISATION

SYSTEMSENSOR

• Signals are input to a sensor, conditioned, converted into bits that a computer can read, and analyzed to extract meaningful information.



Study of LabVIEW



Lab VIEW (Laboratory Virtual Instrument Engineering Workbench.)

• Lab VIEW is a graphical programming language that uses icons instead of lines of text to create programs.

• Lab VIEW is a platform and development environment for a visual programming language from National Instruments.



virtual instruments

• Lab VIEW programs are called virtual instruments, or VIs, because their appearance and operation imitate physical instruments, such as oscilloscopes and multimeters.

• After build the user interface, add code using VIs and structures to control the front panel objects. The block diagram contains this code.



LABVIEW INTRODUCTION

Two “sets” for development Front Panel Block Diagram

Wiring connections

LabVIEW Conventions

Running LabVIEW programs



LABVIEW Front Panel

• It is the user interface for the VI. • Used to display Controls or Indicators.• It contains the Controls palette.• Highly customizable.



LABVIEW Block DiagramThe block diagram provides the area for the graphical code

• Actual program.• Invisible to user.• Read left to right, like a book.

TheFunctions Palette



LabVIEW Palettes

1- The Front panel contains:

The Controls Palette

2- The Block Diagram panel contains:

The Functions Palette



1- Controls Palette • To open the control palette from the front

panel :

• Or click the mouse right button.



• The Controls palette contains the controls and indicators that used to create the front panel.

ControlsIndicators



Some Controls & Indicators



2- Functions Palette • To open the Functions palette from the block

diagram window :

• Or click the mouse right button.



Some Functions



Terminals :

When you place a control

(or indicator) on the

FRONT PANEL

LabVIEW automatically creates a correspondingcontrol (or indicator) terminal on the

BLOCK DIAGRAM



Basic wires used in block diagramsand corresponding types:

• Each wire has different style or color, depending on the data type that flows through the wire:



LabVIEW Conventions

• Front panel items Controls and indicators

• Block diagram items Program structures (loops, case structures, math, etc.)

• Controls vs. Indicators Wires attach to controls on the right (give values) Wires attach to indicators on the left (receive values)

• Wiring colors Wires are color coded to correspond to data types



Controls and Functions Palettes

Graphical, floating palettesused to place controls and indicators on the front panel, or to build the block diagram.

Controls Palette (Front Panel)

Functions Palette (Block Diagram)



Creating a front panel

• Right click to select the controls palette

• Drag and drop the components

• As you place components a corresponding terminal will appear in the diagram window



Wiring the diagram

• Right click to select the functions palette

• Drag and drop functions

• Select the wiring tool

• Drag the wire between terminals





Basic Examples :• LabVIEW is written on graphical structure.

• While in LabVIEW summation is a function and it is represent by following symbol.

• In LabVIEW, such mathematical and logical functions are represented graphically.



Add and multiply two given numbers and display the results



Converting ºC to ºF

°F = (1.8 * °C) + 32

Control

Indicator



Introduction of DAQ card



What is DAQ System

• DAQ systems capture, measure, and analyze physical phenomena from the real world.

• Light, temperature and pressure are examples of the different types of signals that a DAQ system can measure.

• Data acquisition is the process of collecting and measuring electrical signals and sending them to a computer for processing.

• Electrical signals comes from Transducers.



The building blocks of a DAQ system includes:

1. Transducer: A device that converts a physical phenomenon such as light, temperature, pressure, or sound into a measurable electrical signal such as voltage or current.

2. Signal: The output of the transducer.3. Signal conditioning: Hardware that you can connect to the

DAQ device to make the signal suitable for measurement or to improve accuracy or reduce noise.

4. DAQ hardware: Hardware you use to acquire, measure, and analyze data.

5. Software: NI application software is designed to help you easily design and program your measurement and control application (LABVIEW).



Why Signal Conditioning To measure signals from transducers, you must convert them

into a form a measurement device can accept.• Common types of signal conditioning include amplification,

linearization, transducer excitation, and isolation.



What type of device to use

The trade-off usually falls between :

• 1- Resolution (bits) & Code Width

• 2- Sampling rate (samples/second)

• 3- Number of channels, and data transfer rate (usually limited by “bus” type: USB, PCI, PXI, etc.).



Types of Data Acquisition and Control Devices



DAQ Device Properties

DAQ devices have four standard elements:

1. Analog input (AI)2. Analog output (AO)3. Digital I/O (DIO)4. Counter/Timers



USB DAQ :• USB -6008 & USB -6009 Low – Cost USB DAQ.The National Instruments USB-6009 provides basic data acqusition functionality for applications such as simple data logging, portable measurements , and academic lab experiments.The NI USB _6008 and NI USB 6009 are ideal for students.

Create measurement application by programing the NI USB-6009 using LabVIEW and NI_DAQmx driver software for Windows.



Feature of DAQ 6009

• Eight 14-bit analog inputs.• 12 digital I/O lines.• 2 analog outputs. • 1 counter.

Analog Digital

1

32

17

16



DAQ6009 Details

Overlay Label with Pin Orientation Guide

Comb icon Jack

Screw Terminal Blocks

Signal Labels



NI USB-6009 Pins



How to Select DAQ Device & Accessories

• Open the Labview program, in the Block Diagram select functions, express input then select the DAQ Assistant icon.



How to Select DAQ Device(Input & Output Channels)

• Select “Analog Input” so as to input your analog data to the computer and Labview.




• We have 16 physical input channels from ai0 to ai15, select a channel like ai0.




• Select your input voltage setup




• Now make the connections and select test then Run to see the input voltage.




• Example



Introduction of Sensors



LM35

• The LM35 is an integrated circuit sensor that can be used to measure temperature with an electrical output proportional to the temperature (in oC).



What Can Expect When Use An LM35?

• The output voltage is converted to temperature by a simple conversion factor.

• The sensor has a sensitivity of 10mV / oC.• Use a conversion factor that is the reciprocal, that is 100 oC/V.• The general equation used to convert output voltage to

temperature is:

Temperature ( oC) = Vout * (100 oC/V)

– So if Vout is 1V , then, Temperature = 100 oC

• The output voltage varies linearly with temperature.



Why Use LM35s To Measure Temperature?

• Measure temperature more accurately than a using a thermistor.

• The sensor circuitry is sealed and not subject to oxidation, etc.

• The LM35 generates a higher output voltage than thermocouples and may not require that the output voltage be amplified.



How does LM35 work?

• It has an output voltage that is proportional to the Celsius temperature.

• The scale factor is 10mV/oC .• The LM35 does not require any external

calibration or trimming and maintains an accuracy of +/-0.4 oC at room temperature and +/- 0.8 oC over a range of 0 oC to +100oC.• Vc = 4 to 30v• 5v or 12 v are typical values used.



Photo of the LM 35 wired on a circuit board.

– The white wire in the photo goes to the power supply.

– Both the resistor and the black wire go to ground.

– The output voltage is measured from the middle pin into ground .

Power supply

Output voltage Ground



Real Picture

LM35



Result in Block Diagram

Temperature ( oC) = Vout * (100 oC/V)

Convert from Dynamic Data



Result in Front Panel (heating)

XY Graph



Result in Front Panel (cooling)

XY Graph



Thermistor

• Thermistors are built with semiconductor materials and can have either a positive (PTC) or negative (NTC) temperature coefficient. However, the NTC is typically used for temperature sensing.

NTC



• Advantages of thermistors include a very high sensitivity to changes in temperature (having a thermal response of up to -100Ω/°C at 25°C),fast response time and low cost.

• The main drawback of thermistors is that the change in resistance with temperature is highly non-linear at temperatures below 0°C and greater than 70°C.



Electrical Connections of Thermistor

• A simple voltage divider is created with a reference resistor (R1) and the thermistor (RT).

• A constant voltage source is supplied (VREF) with the output of the voltage divider (Vout)directly correlating to temperature.



• The response is shown in the graph of temperature vs. output voltage to the right

• of the circuit. It is fairly linear in the range of 0-70°C.

LINEAR



Why Use Thermistors To Measure Temperature?

• They are inexpensive, rugged and reliable.• They respond quickly.



Thermistor – Block diagram(Heating & Cooling)

Convert temp(F) to (C)

T= ((1/298) +(1/4038)*ln(v/(5-v)))**(-1)*1.8-460 of



Thermistor-Front panel(Heating)



Thermistor –Front panel(Cooling)



Real Picture

Thermistor



AD590 Circuit



Solid State Temperature Sensor(Linear 1 Microamp per Kelvin Output)

• Solid state' temperature sensor has an easy to use linear voltage output, unlike conventional resistive sensors.

• The AD590 is a small temperature transducer that converts a temperature input into a proportional current output.

• The advanced technology in the AD590 is especially suited for special temperature measurement and control applications between -55 and 150°C (-67 to 302°F) when solid state reliability, linearity and accuracy are required.

• The size and responsiveness of the AD590 make it perfect for uses where size is a consideration, such as on PC boards or heat sinks.



Specifications

• Absolute Maximum Ratings• Forward Voltage (E+ to E-): +44V• Reverse Voltage (E+ to E-): -20V• Breakdown Voltage• (case to E+ or E-): ±200V• Lead Temperature: 300°C• Voltage Range: 4 to 30 Vdc• Nominal Current Output at 25°C• (298.2 K): 298.2 μA• Nominal Temperature Coefficient:

1 μA/K

• Calibration Error: J: ±5.0°C maximum (K: ±2.5°C)• Absolute Error: Without external• Calibration Adjustment: J: ±10.0°C max (K: ±5.5°C); W/25°C error set to zero J: ±3.0°C max (K: ±2.0°C)• Repeatability: ±0.1°C max• Long-Term Drift: ±0.1°C/month max



AD590

• The AD590 solid-state temperature sensor produces an output of 100mV per degree Celsius :

Temperature = Voltage * 100• For example we have 0.35(v) in 35(degree

Celsius).



AD590 –block diagram(Heating & Cooling)

Temperature = Voltage * 100



AD590- Front Panel(Heating)



AD590- Front Panel(Cooling)



Response temperature vs voltage

(Heating)



Response temperature vs voltage

(Cooling)



Real Picture

AD590



PT100

• The principle of operation is to measure the resistance of a platinum element. The most common type (PT100) has a resistance of 100 Ω at 0 °C and 138.4 ohms at 100 °C. There are also PT1000 sensors that have a resistance of 1000 ohms at 0 °C.

• The relationship between temperature and resistance is approximately linear over a small temperature range: for example, if you assume that it is linear over the 0 to 100 °C range, the error at 50 °C is 0.4 °C.



Circuit Diagram of PT100



Features

1. Extremely accurate.2. Fairly good linearity.3. Variety of packages.4. Wire wound or thin film.



Applications

1. Industrial instrumentation.2. Hot wire anemometers.3. Laboratory quality measurements.4. Air , gas and liquid monitoring.5. Petrochemical.



Real picture

PT100



PT100-Block Diagram(Heating)

R=100(1+(t*0.00385))



PT100-Block Diagram(Cooling)

R=100(1+(t*0.00385))



PT100-Front Panel(Heating)



PT100-Front Panel(Cooling)



Response graph of temperature vs. output voltage

(Heating)



Response graph of Temperature vs. output Voltage

(Cooling)


