Instrumentation Engineering Overview

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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

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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

alamsyah_syam@yahoo.com

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