Development of sensing and control Centralization control DCS

Development of sensing and control Centralization control DCS, PLC, Remote I/O Communication, network Distributed, Open architecture, Intelligent, Smart I/O Communication , network 2

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Remote Data Acquisition • . Intelligent sensor to controller / computer • . Built-in RS-232/RS-485 • . Built-in Microprocessor • . Programmable I/O • . Wireless - Radio modem module • . Network - Ethernet, control area network(CAN), Lonwork, • . Open architecture • . Friendly MMI (HMI: Human Machine Interface) 6

OPEN I/O Architecture 7

• Open_Control is a programmable controller which is designed based on the Lon. Works communication technology. 8

Field Bus systems in open network 1. ARCNET(Attached Resource Computer Network) 2. PROFILBUS(PROcess Field Bus) 3. Interbus S (EN 50254) 4. SERCOS (Serial Realtime Communication System)- www. sercos. org 5. CAN(Control Area Network) – www. can-cia. de 6. IEEE 1394(Firewire) - www. 1394 ta. org 7. Industrial Ethernet – 8. EIB (European Installation Bus) 9. Lon work(Local Operating Network) 10. others - Controlnet, World. FIP, AS-interface 9

Future Development • . Powerful faster host CPU and accessories • . Friendly MMI(HMI), PC-based, Window-based • . Opened Communication , Network , shared database • . Reliability Hardware/ software • . Low cost competitive, compatibility • . Smarter intelligence( Intelligent ) I/O, DSP, distributed • . Smaller Micro sensor, Micro-mechatronics 10

A smart sensor module 12

Evolution of Instrumentation Flexibility VI Scope(Digital) IC/ASIC CRT Electronic Analog 25 0 50 75 10 0 PC Transistor Vaccum tube TV Radio Clock Time 17

Sampling Rate • Determines how fast A/D conversions take place • Signals must be sampled fast enough to properly reproduce the signal • Aliasing – signal is undersampled Aliased due to undersampling Adequately sampled 21

Simultaneous Sampling • For applications where the time relationship between signals is important Channel 1 • Instrumentation amplifier and sample Channel 2 -and-hold circuitry for each channel • Mux connects channels to the ADC Channel 1 • Example – Four 50 k. Hz signals sampled at 200 k. Hz Channel 2 Channel 1 Channel 2 Channel 3 Channel 4 Round Robin Sampling 15 ms (270 o phase shift) between Ch 1 & 4 Inst Amp S/H Analog Mux Inst Amp ADC S/H Simultaneous Sampling 15 ns (0. 09 o phase shift) between Ch 1 & 4 (SC-2040 or SCXI-1140) 22

High speed sampling rate • Some digitizing oscilloscopes can use equivalenttime sampling to capture very fast repeating signals. • Equivalent-time sampling constructs a picture of a repetitive signal by capturing a little bit of information from each repetition 1 G Hz * 1/1000 = 1 MHz。 即 1 MHz取樣率可擷取 1 G Hz 訊號(週期性訊號) 23

High speed sampling rate • 24

Elements of an Instrumentation System 25

Signal Classification 26

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資料擷取系統- Signal Conditioning 30

Signal Conditioning • Amplification – Maximizes use of ADC range and increases accuracy – Increases SNR Signal Voltage S. C. * Amplification Noise in Lead Wires DAQ Board Amplification Digitized SNR Voltage Amplify only at DAQ Board . 01 V None . 001 V x 100 1. 1 V Amplify at S. C. * and DAQ Board . 01 V x 10 . 001 V x 10 1. 01 V 100 Amplify only at S. C. * . 01 V x 100 . 001 V None 1. 001 V 1000 10 31

Common Types of Signal Conditioning Transducers/Signals Thermocouples RTDs Strain Gauges Signal Conditioning Amplification, Linearization, and Cold-Junction Compensation Current Excitation, Four Wire and Three Wire Configuration, Linearization Voltage Excitation, Bridge Configuration, and Linearization DAQ-STC Common Mode or High Voltages Isolation Amplifiers (Optical Isolation) Loads Requiring AC Switching or Large Current Flow Electromechanical Relays or Solid-State Relays Signals with High Frequency Noise Lowpass Filters DAQ Board 32

Signal Conditioning • Transducer Excitation — External voltage or current applied to transducer — Provided by signal conditioning hardware • Linearization — Most transducers are not linear — Can be done in hardware or software • Isolation — Protects hardware from high voltages — Used in systems with high common-mode voltages • Filtering — Remove noise or unwanted signals — 4 Hz filter (SCXI-1121) optimum for removing 60 Hz AC noise from slowly sampled signals — Antialiasing filters 33

Signal Grounding and Measuring Techniques Signal Sources and Measurement Systems Rs • Grounded • Floating + - Vs Measurement Vm System • Differential • Referenced Single-Ended(RSE) • Non-Referenced Single-Ended (NRSE) Grounded Signal Source • Plug-in instruments with non-isolated inputs Floating Signal Source • Thermocouples • Signal conditioning with isolated outputs • Battery-powered devices 34

Signal Connections Differential Grounded ? RSE NRSE Floating 35

Measuring Grounded Sources • Best method – differential • Can also use NRSE (uses fewer channels) • Both methods avoid ground loops* Correct Incorrect + + + - Vs < DVg > + = - Vs + - DVg Ground referenced measurement system Vs < DVg Grounded signal source Source Ground = - - Vm = Vs + DVg Grounded signal source + > + + Vs + DVg - Vm = (Vs + DVg) - (DVg) = Vs Nonreferenced or differential measurement system Measurement System Ground * Ground loops: – Difference in potential between source ground and measurement system ground – Often appears as 60 Hz noise 36

Measuring Floating Signal Sources • Measure with differential, RSE or NRSE • Differential or NRSE — Use bias resistors (10 k. W to 100 k. W) — Ensure common-mode voltage does not exceed board limits • RSE or NRSE — Use when signals are high and noise is low — All signals should be commonly grounded at the source + + - R 1 R 2 Bias current injected into system by the instrumentation amp Resistors (10 k. W < R < 100 k. W) provide a return path to ground for instrumentation amplifier input bias currents. Only R 2 is required for DC-coupled signal sources. For AC-coupled sources, R 1 = R 2. 37

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模組化的軟體架構 重覆使用率 80% 50% 90% Test Exec 報表 Test Management Services SQL SPC 程序 儀器驅動程式 42

PC-based DAQ架構 控制及應用軟體 硬體及驅動程式 PC or Workstation Application Software DAQ Products Processsensor, Actuators Serial Instruments GPIB Instruments Unit to be Tested/ measured VXI Instruments 44

DAQ solution 軟體支援 Application Software • Lab. VIEW • Lab. Windows/CVI • MATLAB • Visual Basic • C/C++. . . Interface Software • Driver(NI-DAQ) Mac, DOS, Win 95/98/ NT Data In/Out DAQ Board PCI/ISA 45

量測自動化利器 IEEE 488. 2 • 電腦控制量測儀器 – – 簡化儀控流程(儀器驅動程式) 數據收集及測試決策可同時進行 人機 Remote Access Plant Digital Scope Device GPIB Ethernet Desktop PCI ISA MAC SUN Portable PCMCIA Parallel Serial Wireless 46

選擇DAQ卡考慮項目 Test & Measurement World Survey 硬體可靠度 準確度 軟體可靠度 使用容易 整合性 技術支援t 先進技術 價格 價值 長期成本 廠牌 產品選擇性 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% Test & Measurement World 1995 PC-Based Test Market Insight Study 47