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Instrumentation Engineering Overview
DOC ID
Alamsyah S.Senior I&C Engineer – PT Slipform Indonesia
Today’s Presentation
• Objective
• Instrumentation in the Process Industry
� Function of instrumentation
� Manual control vs. Automatic control
� Measured parameters
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� Measured parameters
• Projects Engineering (Where It Begins)
� Basic instrument engineering
� Aided software (INtools) overview
• Job Outlook
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Objective
• The objective of this presentation to share the
role of instrumentation engineer in industrial
environments
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Instrumentation in the Process Industry
• The function of instrumentation system can be
classified into the following categories:
�Value or quality assessment
�Safety and protection
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�Automatic Control
�Data collection
4
Manual Control
• Example of manual control:
To regulate the level, the
tank is provided with a
glass “sight tube”, S, as
shown in Figure 1.1. The
actual liquid level or height,
h, is called the controlled
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h, is called the controlled
variable. In addition, a
valve has been added so
the output flow rate can be
changed by the operator.
The output flow rate is
called the manipulated
variable or controlling
variable.
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Automatic Control
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• To provide automatic control, the system is modified as shown in Figure 1.2 so machines,
electronics, or computers replace the operations of the human. An instrument called a sensor
is added that is able to measure the value of the level and convert it into a proportional
signal s. This signal is provided an input to machine, electronic circuit, or computer, called
the controller. This performs the function of the human in evaluating the measurement and
providing an output signal u to change the valve setting via an actuator (motor or a
pneumatic system) connected to the valve by mechanical linkage. This a typical example of
automatic process control.6
Physical Quantities for Measurement
• Temperature
• Pressure
• Flow
• Level
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• Weight
• Etc.
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Types of Controls
• On-Off Control:
� Solenoid valve, Heating element, Electrical
contactor, etc.
• Continuous Control:
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• Continuous Control:
� Control valve, Damper, etc
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Temperature Measurement
Thermometers � Expansion Thermometers
� Filled System Thermometers
Measuring Elements
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Electrical Instruments
Pyrometers
� Resistance Thermometers
� Thermocouples
� Thermistor
� Radiation Pyrometers
� Optical Pyrometers
Temperature Measurement
• Most Commonly Used Measuring Elements:
� Thermocouples
Principle: a current flows in a closed circuit made
up of two dissimilar metals if the junctions of the
two metals are kept at different temperatures.
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two metals are kept at different temperatures.
Thus the EMF generated is proportional to the
temperature difference in a predictable manner.
This phenomenon is known as Seebeck effect.
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Temperature Measurement
• Most Commonly Used Measuring Elements:
� RTD (Resistance Temperature Detectors)
Principle: the resistivity of metals increases or
decreases with increase in temperature. Such
variation can be measured precisely with suitable
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variation can be measured precisely with suitable
electrical circuits. Used for low temperature, high
accuracy measurement.
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Temperature Measurement
• Selection Criteria
Temp Range Type of Transducer Type
900 degC RTD Platinum
400 degC RTD Nickel
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700 degC Thermocouple T (Cu-Constantan)
900 degC Thermocouple Y (Fe-Constantan)
1370 degC Thermocouple K (NiCr-Ni)
1700 degC Thermocouple R (Pt87,Rh13-Pt)S (Pt90,Rh10-Pt)
3700 degC Radiation Pyrometer
Temperature Measurement
• Typical Arrangement
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Pressure Measurement
Manometers
Measuring Elements
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Elastic Transducers
Electrical Transducers
Pressure Measurement
• Most Commonly Used Measuring Elements:
� Manometers
Orifice
Flow
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hhhh
Scale
h1h1h1h1
h2 h2 h2 h2 High Pressure Tap P1
Low Pressure Tap P2
P= (ρρρρ- ρρρρ1) g hWhere ρ= Density of fluid in U tube
ρ1= Density of fluid in pipeh = h2-h1g = acceleration due to gravity
Pressure Measurement
� Diaphragm Transducer
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Pressure Measurement
• Typical Arrangement
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Flow Measurement
• Determination of proportions and amount of
materials flowing in or out of a process.
• Various Methods For Flow Measurement
�Variable head or differential
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�Variable Area
�Magnetic
�Thermal
�Ultrasonic
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Flow Measurement
• Differential Flowmeters:
� Principle:
Orifice
Flow
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∆P
Flow α √ ∆P
Flow Measurement
� Magnetic Flowmeters
� Principle: uses Faraday’s law of EMI “whenever a
conductor moves through a magnetic field of given
strength, a voltage is induced in the conductor
which is proportional to velocity between the
conductor and the magnetic field”
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conductor and the magnetic field”
� In case of magnetic flowmeter, electrically
conductive flowing liquid acts as a conductor.
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Level Measurement
Direct Methods
Measuring Methods
� Hook Type
� Sight Glass
Float Type
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Indirect Methods
� Float Type
� Hydrostatic Type
� Electrical Type
� Pressure Type
� Bubbler Type
� Capacitance Type
� Radiation Type
Level Measurement
�Open Tank �Closed Tank
• Pressure Type
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PressureTransmitter
DifferentialPressureTransmitter
Level Measurement
• Capacitance Type
Insulated Capacitance ProbeElectric Wires
Metal Tank
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Capacitance measuringInstrument calibratedIn terms of level
Liquid (as dielectric)
C=K . A/D Where C = CapacitanceK = Dielectric ConstantA = Area Of PlateD = Distance Between Plates
Level Measurement
• Radiation Type
Electric Wires
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Operating range of Level
Source
Co-60
Detector
Plant Life Cycle
• Instrumentation is part of the entire plant life cycle
Processideas
InitialConcept
Detaileddesign
Construction OperationBasicdesign
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Instrumentation
Where It Begins
• Project Managers in many organizations are also
the marketing arm; as such they try hard to please
the client and be awarded the contract.
• An engineering estimate is always necessary and
usually generated based on client’s SOW or a
preliminary P&IDs. Each discipline (Civil,
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preliminary P&IDs. Each discipline (Civil,
Structural, Project Control, Mechanical, Process,
Piping, E&I) develops an estimate, and then PM
team assembles it for presentation to the client. If
the client accepts the proposal, the contract may
be awarded & the project is initiated.
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Deliverable Checklist
• Scope of Work
• Design Criteria Study
• P&ID
• SAMA Diagrams
• Instrument Index
• Specifications, Data Sheets
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• Specifications, Data Sheets
• I/O List
• Block Diagrams
• Loop Diagrams
• Hook-up Drawings
• Cable Schedule
• Material Take-Off
• Etc.
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Manpower Forecast
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Piping & Instrumentation Diagram
• P&ID shows all of piping including the physical
sequence of branches, reducers, valves,
equipment, instrumentation and control interlocks.
• P&IDs are a shared responsibility of the
Instrument, Mechanical, and Process departments.
One of them must take the responsibility for the
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One of them must take the responsibility for the
drawings and drafting. Most often in is the
Mechanical department.
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Piping & Instrumentation Diagram
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Instrument Index
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Block Diagram
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Instrument Specification
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Wiring Diagram
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Hook-up Drawing
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Job Outlook
• With global health and energy challenges rising,
the demand for engineers continues to grow, and
engineering salaries continue to rise as well.
• A total of 4,674 engineers from around the world
responded to the online salary (automation.com
and intech online) survey between May 24 and
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and intech online) survey between May 24 and
August 19, 2013, providing insights into salaries
and the job market
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Job Outlook
• Average salary by region of the world
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Job Outlook
• Average salary by work experience
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Job Outlook
• Jobs are so plentiful in some areas of the
nation and world that companies are designing
their own training programs to help meet the
demand. For those seeking a stable career
with excellent pay, great benefits and a
variety of tasks during the workday there are
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variety of tasks during the workday there are
few jobs better than that of an instrument
engineer
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Documentation
• Some documentation is available here,
please contact me directly or the forum
organization.
• Documentation may be requested at the
following email addresses
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following email addresses
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