Computerized Measurement Systems (EEMN10) 2015bme.lth.se/.../EEMN10_2015_Lect1_Introduction.pdf ·...

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Computerized Measurement Systems (EEMN10) 2015CHRISTIAN ANTFOLK & JOSEFIN STARKHAMMAR

Course information 2015• Course administrators:

Christian Antfolk ([email protected])Josefin Starkhammar ([email protected])

• Course webpage : http://bme.lth.se/course-pages/datorbaserade-maetsystem/

Lund University | Faculty of Engineering | Dept. of Biomedical Engineering

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Course information 2015


Course information 2015• Goal: to give an overview of systems and methods to collect

measurement data with the help of a computer in test and industrial environments. To program such a system in eg.LabVIEW or Matlab in a logical and structured way in order to solve a measurement task.

• Lectures: Lectures in this room (E:1328), Mondays & Fridays• Course litterature: Will be made available on the course

webpage• Grades: Passed assignments (handed in on time!), laboratory

exercises and project = grade 3. Higher grades require taking the exam.

• If you decide NOT to follow the course please let us know


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Course information 2014

• 3 Assignments– Assgn 1: LabVIEW (Hand-in deadline Sunday 15.11.2015)

– Assgn 2: DAQ Boards (Hand-in deadline Sunday 22.11.2015)

– Assgn 3: Home Lab (Hand-in deadline Sunday 13.12.2015)

• 2 Labs– Lab 1: GPIB (Academic week 3, room E:1309b)

» Wednesday 18.11.2015 8-12 or 13-17

– Lab 2: DAQ-PAD (Academic week 4, room E:1309b)» Wednesday 25.11.2015 8-12 or 13-17


Course information 2015• Project:

– Build a measurement system (room E:1309B)– Choose project week 3 of the course– Short project description and suggested approach to

solution Monday 29.11.2015– Short oral presentation Monday 14.12.2015 + written

report– Report hand-in Friday 18.12.2015

• Gear : PC with LabVIEW and Matlab


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Example projects (last year)

• FPGA/CompactRIO-based measurements (industry)• Automated Voltage vs. Frequency measurement for an

acoustophoresis setup (BME)• Control of pneumatic actuators for stimulation in an fMRI

environment. (Radiation Physics / BME)


Schedule (subject to change)


Preliminary schedule for EEMN10 2015Academic week Day Date Time Place

Lect no: Topic Lecturer Assignments

Labs (E:1309b) Project

1 Monday 02.11.2015 13‐15 E:1328 1Introduction to the course CA

Friday 06.11.2015 13‐15 E:1328 2 LabVIEW I (introduction, variables, structures etc) JS

2 Monday 09.11.2015 13‐15 E:1328 3LabVIEW II (subVI's, error wires, data flow control) :: Assgn 1 info JS Assgn 1: LabVIEW(Deadline

Sunday 15.11.2015)Friday 13.11.2015 13‐15 E:1328 4 Databuses and communications : Project suggestion list CA

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Monday 16.11.2015 13‐15 E:1328 5 Instrument control :: Lab1 and Assgn 2 info & prep JS Assgn 2: DAQ board (Deadline

Sunday 22.11.2015)

Lab1 : GPIB

Friday 20.11.2015 13‐15 E:1328

6 LabVIEW in industry / Design patterns DVEL

Choose project

4Monday 23.11.2015 13‐15 E:1328 7

Data acquisition boards and USB‐DAQ :: Lab 2 info & prep

CALab2: DAQ‐

PAD

Project plan (Deadline Sunday

29.11.2015)

Friday 27.11.2015 13‐15 E:1328 8Data acquisition using Matlab :: Assgn 3 info & prep + LabVIEW @ Elmät JS

Project execution

5 Monday 30.11.2015 13‐15 E:1328 9Signal conditioning CA

Assgn 3: Home Lab assignment (Deadline

13.12.2015)

Friday 04.12.2015 13‐15 E:1145 10 Signal processing data presentation, questions and check‐up CA

6 Monday 07.12.2015 13‐15 E:1328 11Software for measurement systems (LabCVI, Measurement Studio, HP‐VEE, Dasylab) CA/GUEST

Friday 11.12.2015 13‐15 E:1328 NO LECTURE

7Monday 14.12.2015 08‐17 E:1328 12 Project presensation / demonstrations CA/JS

Friday 18.12.2015 13‐15 E:1328 NO LECTUREReport hand‐in

8 Wednesday 13.01.2015 8‐12 E:1328 EXAMINATION

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Overview of the course content


Computerized measurement system example

Physical quantity Measurement system

Signal processing


Sensor

Physicalquantity, eg. soundwave

Signal conditioning, eg. filters & amplifiers

Instrument withdata bus

interface, eg. USB or PXI

Personal computer

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Structure of a measurement system


• pressure• temperature• speed• angular velocity• luminosity• force

Physicalquantity

Measurementsystem

Presentation(and control)

• Signal conditioning• DAQ-cards• Bus control of

instruments• GPIB (parallel)• RS232 (serial)

• Bus systems with integrated and standardized instruments• VXI/PXI• Real time controllers• Field buses

• Graphical programming• LabVIEW• Agilent VEE• DASYlab

• Textual programming• LabWindows CVI• Measurement Studio• Visual Basic• Visual C/C++• Matlab




Physicalquantity

Measurementsystem







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Signal conditioning


• How does the sensor/transducer work?• Change in resistance (strain gauge, Pt100) -> Wheatstone bridge• Voltage (thermocouple, piezo transducer)• Current (semi-conductors) -> generate known voltage drop over

known R

• Filterering (50 Hz), isolation (opto), amplification?• A/D conversion

• Adapt the signal to the working range of the A/D converter• Dynamic range (Difference between the smallest and biggest

measurable values)• How many bits (resolution) does the measurement system has to

have to meet the need for measurement accuracy? (8 bits = 2^8=256 signal levels across the measurement range)(+ 10 V => 78 mV per level. 16 bit => 0.3 mV per level)




Physicalquantity

Measurementsystem







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Example of a DAQ card


• Programmable range• 2 x 12-bit Analog Outputs• Internal or external trigger

• 16 Analog inputs• 12-bit A/D converter• 1 multiplexed A/D converter• 110 kHz sampling frequency




Physicalquantity

Measurementsystem







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General Purpose Interface Bus

• Introduced by HP 1965• 1 MB/s• Requires special cables and och plug-in cards• Max 20 m total cable length and 15 instruments• Still very much used for instrument control in both industry

and research environments, probably due to the rugged connectors


General Purpose Interface Bus


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Physicalquantity

Measurementsystem







Serial communications• RS-232

– Unbalanced (one ground wire + one active wire)

– Point-to-point

– Up to 19,2 kbit/s at 15 m cable

• RS-422– Balanced (both wires are active but in opposite phase)

– Point-to-point

– Up to 2 Mbit/s

• RS-485– Balanced (both wires are active but in opposite phase)

– Multiple units are connected in parallel, however the communication is serial (Multidrop)

– Up to 10 Mbit/s


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Comparison RS232 – RS422


Tx

GNDRS232

Tx-

Tx+

RS422/RS485

0

1

Serial communication


• USB, FireWire, Ethernet– 5 m cable for USB, – 5 Gbit/s (USB 3),

• FireWire– 72 m cable– 3.2 Gbit/s

• Ethernet– 72 m cable– 10 Gbit/s

• SATA 3– 8 m cable– Up to 6 Gbit/s – Designed to send data quickly to harddrives

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Example of USB based system





Physicalquantity

Measurementsystem





• Graphical• LabVIEW• LabCVI• Measurement Studio• Agilent VEE• (DASYlab)

• Command• LabWindows• Visual Basic• Visual C/C++• Matlab

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What is a computer bus?

• A collection of wires which transfer digital data according to a specific protocol between separate units.

• There are several standards to allow seamless connectivity of instruments from a number of different vendors.

– Example : PCI, USB, GPIB, Firewire, SATA, Ethernet, etc

• Example of entire systems with specific computer buses incorporated in each unit are fieldbuses, VXI-systems, PXI-systems, real-time controllers etc.


The PCI bus in a PC

• The PCI-bus, 32 bits, 133 MB/s, 33 MHz• ”Peripheral Component Interconnect”• The PCI-e bus, ”PCI-express”, 64 bits, 256 MB/s per line

(total of 20 lines), 2 GHZ• Full duplex = to send and receive data at the same

time => 512 MB/s


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VXI – VMEbus eXtensions for Instrumentation• Faster and more compact than

GPIB (40 MB/s with a 32 bit bus)

• Produced by 250 vendors• Can be connected through

MXI (Multisystem eXtensionInterface), or GPIB if there are other more traditional instruments in the system

• FireWire (IEEE-1394), USB, LAN etc…


PXI – PCI eXtensions for Instrumentation

• Like VXI but with PCI bus• More compact, ”cheaper”• Also PXIe for the faster PCI

express bus


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Real time controllers• Basic idea: combine measurement

tasks and signal generation with dedicated hardware

• Advantages: fast, robust• Car industry, power industry,

automation• Plug in cards• Stand alone module• Industrial systems


Fieldbuses

• Used to interconnect automation devices in a network• Heavily used in industry


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Fieldbuses


Fieldbuses - example

• Cars (CAN-bus)• More and more gadgets and driver aid systems has

increased the total weight of the wiring in cars. (Engine control systems, ACC, ABS, ESP...)

• Gambro’s AK100• Elevators• Photo copy machines• Toys


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Why use fieldbuses

• Distributed intelligence gives:• Less cabling, especially over long distances• Measurement cells can be made self calibrating or be

calibrated remotely through the bus• Self diagnostic systems• Flexible system when transducer units are exchanged





Physicalentety

Measurementsystem





• Graphical• LabVIEW• LabCVI• Measurement Studio• Agilent VEE• DASYlab

• Command• LabWindows• Visual Basic• Visual C/C++• Matlab

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LabVIEW

• National Instruments• Graphical Programming Language• ”G”• Current version LabView 2014• Virtual Instruments


Virtual instruments

• Three mail building blocks:• Data collection (software for communication with

measurement device, e. g. ordinary instrument, DAQ-card or through VXI/PXI)

• Analysis (statistics, filtering, spectral analysis...)• Presenation (all settings can be handled through the

program window which is designed for the specific measurement task, data presentation etc. Hence, the name Virtual Instrument)


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Example of a LabVIEW program• Front panel


Example of a LabVIEW program• Block diagram


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Dataflow programming

• Execution determined by the structure of the program


A poor example of a LabVIEW program


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A better example of a LabVIEWprogram


Download LabVIEW & Matlab

• LabVIEW– Go to http://www.ni.com/academic/download.htm– Download LabVIEW– Student serial number : M79X96296

• Matlab– Go to http://program.ddg.lth.se/– Log in– Follow the instructions


Computerized Measurement Systems (EEMN10) 2015bme.lth.se/.../EEMN10_2015_Lect1_Introduction.pdf ·...

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