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

Example: DESY in Hamburg

Example: DESY in Hamburg

Process InstrumentationChemical Process

Source: Siemens process

instrumentation

and analytics

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: Flowmeter

• Ultrasonic flowmeter

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