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Process Measurement Engineering
1. Introduction to Process Measurement Engineering
2. Fundamentals
3. Sensors
4. Amplification and Analog to Digital Converters
5. Data Transmission and Data Systems
Literature
• J. G. Webster (Editor): “The Measurement, Instrumentation, and Sensors
Handbook” CRC Press, 1999.
• H. Kronmüller: “Prinzipien der Prozeßmeßtechnik 1”, Schnäcker-Verlag 1986
• Bracewell, R.: ”The Fourier Transform and Its Applications”, 3rd ed. New
York: McGraw-Hill, 2000.
• Weisstein, Eric W.: “CRC Concise Encyclopedia of Mathematics”, 2nd
Edition, Chapman & Hall/CRC, 2002, http://mathworld.wolfram.com/
• H. Kronmüller, B. Zehner: “Prinzipien der Prozeßmeßtechnik 2”, Schnäcker-
Verlag 1980
Definition of Process Measurement
Engineering
• What is process measurement engineering?
• What is the difference in comparison to scientific
measurement engineering?
• What are the requirements for process measurement
instrumentation?
Scientific measurement technology
• Measurements in order to validate scientific theories
• Test for all scientific theories
• Measurements may take years (e.g. Super-
Kamiokande experiment)
• Equipment may be large (e.g. DESY)
• Experiments may involve many scientists
• Automation is not required
Process Measurement Technology
• Measurements are performed in order to enable or
optimize a process
• Qualitative and quantitative measurements of matter
(gas, liquid, solid):
• Analysis of species: atoms, molecules, solids
• Quantification (e.g. mass, concentration)
• Quantitative Measurement of physical quantities (e.g.:
energy, temperature, charge)
• Measurements within automated (industrial)
processes
• Monitoring and surveillance
Requirements for process measurement
techniques (I)
• Measurements should be performed automatically
• Measurements should be performed within short periods
of time
• The process should not be influenced
• Goals for the accuracy (trueness) and precision are
strongly dependent on the process
• Operational availability and reliability must be high
• Amount of maintenance should be low
Requirements for process measurement
techniques (II)
• Systems should be rugged because they are often
mounted directly at the production line
• Varying temperatures
• Dust
• Vibrations
• Electromagnetic interference
• Systems have to be stable over long periods of time (no
aging of the systems)
Instrumentation of Processes:
Classical InstrumentationManagement
Operating staff
CO
C
AD A
A
S S Plant
Control center
Control channels
SA
Actuator
(valve)
SensorAmplifier AD Analog/digital
Process Automation
Process
Parallel Measurement/Control
PT Flow Composition
System 1 System 2 System 3 System 4
• Complex control not possible
Process
Central Measurement/Control
• Failure of central computer causes
complete stop of process
• Solution:
• Backup system
• Distributed process automation
Distributed Process Automation
R MPC
R
AU1 AU
2AU
n…….
R
AU1 AU
2AU
n…….
WAN
LAN
Sub process 2Sub process 1
MPC - Main Process Computer
R - Router AUn - Automation Unit
Management and
Coordination
Level
Process Level:
Measure
Control
Monitoring
SPC SPC
SPC - Sub Process Computer
LAN LAN
Example: CVD Process Measurement
• Monitoring of chemical vapor deposition process• Production of thin films on semiconductors
• Chemical reaction at the surface of a semiconductor
• Example: AX(g) + H2(g) <===> A(s) + HX(g)
• Gas composition, temperature and flow have to be monitored
• Measurement of gas composition during deposition and chamber clean
• Detection of leaks
• Mass spectrometer