Role of NI Products in Thermophysical & Optical Instrumentation

Transcription

1 Role of NI Products in Thermophysical & Optical Instrumentation T G RAMESH Materials Science Division National Aerospace Laboratories Educator s Day 2008 National Instruments 21 st Nov 2008

2 Materials Science Division of National Aerospace Laboratories, Bangalore is actively involved in R & D Activities related to Materials Characterisation of materials Thermophysical Instrumentation Optical Instrumentation Collaborators: Dr V Shubha Ms Florita D Sa Mr Siva Kumar

3 Talk deals with Indigenous Development of Instrumentation 1. Thermo-Physical Techniques/ High Precision Instruments 2. Airport Instrumentation --- DRISHTI

4 PXI AC Resistivity System Thermopower Analyser IEEE DC Resistivity AC Sp heat System PCI - Card DTA Apparatus LabView 8.5 Software Thermal Cycling Apparatus

5 Temperature Programmer Heart of the Thermo-Physical Instrumentation SIGNAL AMPLIFIER WITH CJC 16 BIT A/D SAMPLE PC BASE D DAS Temperature range : C POWER AMP D/A Temperture Linearising Software & PID Simulator Temperature Stability : ± 0.05 C Software selectable rate of heating : C/min Temperature linearisation (6 th order polynomial) Temperature Control (Proportional Integral Derivative ) Data acquisition using A/D, D/A Averaging of the data for improved S/N ratio Real time graphic display of physical property of interest vs temp for on line observation of thermal event in the sample Customized soft ware in different environments like VB and Lab View.

6 Temperature Programmer Heart of the Thermo-Physical Instrumentation Temperature range : C Temperature ( o C) o C/min 5 o C/min Time (minutes) Rate of Heating plot Temperature ( o C) Time(minutes) Temperature stability plot (± 0.05 C)

7 Electro Thermal Analyzer Current Amplifier AC DC Resistivity Technique Four-Probe Method Lock in Amplifier SAMPLE TEMPERATURE PROGRAMMER PC BASED DAS Oscillator POWE R AMP System based on an oscillator with facility for Lock-in-detection Resolution in resistivity measurement Part in 1000 Software selectable rate of heating to 20 C/min Integrated with PCI bus Data Acquisition Card & also IEEE bus Software for data acquisition with real time graphics developed under Lab View R vs T in a Shape Memory Alloy Resistance (m ) 2.10 Heating 2.05 Cooling Temperature( o C)

8 ABSOLUTE TEP MEASURING TECHNIQUE Differential mode of measurement for enhanced resolution V 13 Seebeck voltage across Cr-S-Cr V 24 Seebeck voltage across Al-S-Al S Cr & S Cr-Al TEP of Chromel & Chromel- Alumel V13 S ( T ) = SCr ( T ) + SCr Al ( T ) ( V13 V24 ) Software Linearisation of Temperature (6 th Order Polynomial ) Temp Range : C Online simulation of Temperature dependence of SCr and SCr-Al Precision Computation of the relation Both the mean temperature T & the temperature difference T can be controlled Temperature Stability: ± 0.1 C Unique provision for keeping T fixed while T can be varied from 0.1 C to 20 C Resolution in TEP: 0.1µV/ C

9 Thermopower Analyser (TEPA) TEP is the most sensitive among the electronic transport properties Science behind thermocouples Powerful characterisation technique in the design of Peltier /thermoelectric coolers, Thermoelectric Generators (High figure of merit Energy materials) A useful tool in estimation of Carbon in steel Temperature range: C Temperature Stability: ± 0.1 C Resolution in TEP: 0.1µV/ C

10 DIFFERENTIAL THERMAL ANALYSER Alumel Temperature Range : 25 C-1000 C Chromel A conventional tool to study physical and chemical changes in the system PC based DAS with real time graphics Rate of heating: 0.5 to 20 o C/minute Ref: Alumina Heating Rate: 10 C/min Furnace DC µv Amplifier Sa m Ref Power Amp Temp Programmer DTA is a technique to record thermal events in the sample by comparing it with a reference material, which is devoid of any physical or chemical changes in the temperature range of interest DTA of CuSo 4 5H 2 O PC DAS

11 AC Specific Heat Measuring System New generation modulated technique with high sensitivity for thermal characterization of materials with a unique feature of simultaneous measurement of AC resistivity of metallic samples Oscillatory heat input to the sample at a frequency ω Leads to a temperature oscillation in the sample at a frequency 2ω The amplitude of the temperature oscillation T ac is inversely related to the specific heat C p of the sample C P = 2 I 0R mω T ac Dedicated IEEE488.2 software Real time Graphics Temp Range C Sensitivity : 10-9 V Ferromagnetic Paramagnetic Transition in Nickel I 0 -- Current, R -- Resistance m -- Mass of the sample

12 TRANSMITTER DRISHTI RECEIVER Embedded hardware Software Front Panel VISIBILITY A parameter of vital importance to the pilot during landing and take off operations NAL has recently developed a state of the art visibility measuring system DRISHTI

13 DRISHTI FIELD SITE OPTO-MECHANICAL SYSTEM Light transmitter with mechanical chopping Two receivers with photopically corrected photo detectors Embedded electronic hardware. Choice of platforms electronic hardware for embedded Field programmable gate arrays (FPGA) Instrumentation extension of PCI bus (PXI) 16 bit microcontroller SIX Installations are currently working Real-Time Controller Drishti at INS HANSA Goa NI CompactRIO Reconfigurable Embedded System 1. Cochin International Airport Limited 2. INS Hansa (Goa) ; INS Garuda (Cochin) 3. Lucknow Airport I/O Module

14 Validation of Data Inter-comparison of data from Drishti and LT 31 Vaisala (Finland) Static Test Neutral Density Filter % Transmission MOR (meters) DRISHTI MOR (meters) LT-31 LT- 31 DRISHTI Model (II) Dynamic Test Fog at Bangalore on 14th January LT-31 Vaisala On 14 th January 2008 MOR (Meters) Drishti 0 5:45:36 6:14:24 6:43:12 7:12:00 7:40:48 8:09:36 8:38:24 Time