Process Line Diagrams, Symbols and Standards

19AEI-406.66

29AEI-406.66 2

General Instruments

• General instruments can be represented in a circle

called balloon.

• Inside the balloon will be a code.

• Code gives the information regarding the function and

nature of the device.

39AEI-406.66 3

1. Instrument - Locally mounted

2. Instrument - At control centre

3. Instrument - Bifunctional / Two services

4. Instrument - Transmitting

49AEI-406.66

Level Meters Flow Meters

59AEI-406.66

Flow measuring Instruments Symbols

69AEI-406.66

79AEI-406.66

89AEI-406.66

99AEI-406.66

109AEI-406.66

Sensors

119AEI-406.66 11

Instruments

129AEI-406.66 12

Converts

139AEI-406.66

Symbols for Different types of Transmitters

S.No: Name of the Transmitter Symbol

1 Pressure transmitter

2 Flow transmitter

3 Level transmitter

PT

FT

LT

∫

∫

149AEI-406.66

159AEI-406.67

Valve

Control valve

Manual valve

Basic Symbols for Different types of Control Valves

169AEI-406.67 16

Back draft damper

Needle valve

Butterfly valve

Basic Symbols for Different types of Control Valves

179AEI-406.67 17

Diaphragm valve

Ball valve

Basic Symbols for Different types of Control Valves

189AEI-406.67 18

S. No Name of the valve

1 Electrically operated control valve

symbol

2.Hydraulically operated control valve

Basic Symbols for Different types of Control Valves

199AEI-406.67 19

3 Pneumatically

operated control valve

4 Safety valve

5 Self actuating valve

209AEI-406.67

Different valve symbols

219AEI-406.67

229AEI-406.67

239AEI-406.67 23

S.No Name of the controller symbol

1. Pneumatic flow controller ∫ // //

2. Pneumatic pressure controller ∫ // //

3. Electronic flow controller ∫

4. Level controller

FC

PC

FC

LC

249AEI-406.67 24

Controllers

259AEI-406.68 25

Line Diagrams

• Electric line

• Pneumatic line

• Hydraulic line

• Capillary line

• Fluid pressure line

269AEI-406.68 26

• Process line

• Point of measurement

• Orifice installed line

• Sonic or U V radiation

• Undefined signal line

Line Diagrams

279AEI-406.68

• Electro magnetic or sonic signal

• Internal system links

• Mechanical link

• Electric binary signal -----\----\----\-----

• Pneumatic binary signal

Line Diagrams

289AEI-406.68

AEI-504.7029

Procedures &Instructions

• For combination instruments that measured more than

one kind of variable or that provide more than one kind

of function, each portion of the combination shall have its

own Identification.

• The Instrument or equipment common to two processes

shall utilize both identification. For example, a

combination recorder for flow and pressure would be

PR-1 & FR-5.

AEI-504.7030

• Multiple or point instruments with all points of same

general service, and all providing the same functions,

shall have one identification.

• The separate elements and their components shall be

identified by suffix numbers added to the number of the

item. Ex: TR-1-1, TR-1-2 etc.

AEI-504.7031

• For remote transmission instruments both the receiver

and the transmitter shall have the same identification , in

agreement with over all service and function of the item.

• Each control valve shall have the identification as the

control instrument by which it is activated.

• When more than one valve is activated by the same

controller ,they shall be identified by suffix letters added

to the number of the item.

Ex : TRC-1a,TRC-1b etc.

AEI-504.7032

• Where Accessories such as

• valve Positioners

• air sets

• switches

relays etc., requires identification, they shall be

assigned the same identification as the instrument

to which they connect or with which they are used.

AEI-504.7033

• Primary measuring elements shall be assigned the same

identifications as the instruments to which they connect.

• Where an element does not connect to any instrument ,

such isolated item shall be assigned separate primary

element identification.

9AEI-406.71 34

P&I DIAGRAM

• A standard form and set of symbols are used in the

preparation of drawings of process control systems

• The drawing is often referred to as piping &

instrumentation ( P & I ) drawing

• The diagram is called as P&I diagram

9AEI-406.71 35

• The P&ID are definitive and comprehensive diagrams

showing all of the equipment, piping, valves and

instrumentation.

• All items must be identified using a standard numbering

system.

• The number should include a size, material and fluid

contents.

9AEI-406.71 36

• P & ID is a detailed graphical representation of a process

including the hardware and software

(ex: piping, equipment, instrumentation) necessary to

design, construct and operate the facility

9AEI-406.71 37

Use of letter code in identification of instruments

The following rules and instructions are used in use of

letter code for identification of instruments.

• Letters of English alphabet are used in letter code.

• All identifying letters shall in all cases be written in

upper case.

9AEI-406.71 38

• The maximum number of identifying letters in any

combination shall be three. The only exception is in the

use of PH or chemical symbols such co2 pair is treated as

a single letter.

• A letter shall have only one identification or significance in

its use as a “first” letter in any combination to define the

process variable.

9AEI-406.71 39

• A letter shall have only one definition or significance when

used as either the “second” or the “third” letter in

combination to defined type of device.

• No hyphens shall be used between letter or combinations

of letters.

• Use of letter codes and their significance of first, second or

third place can be easily understand by the given table.

9AEI-406.71 40

TABLE Meanings of Identification Letters

Identification Letters

First Place (Measured or

Initiating Variable)

Second Place (Read out or

Passive function)

Third Place (Output function)

A Analysis Alarm -

B Burner, flame User 's choice User's choice

C Conductivity -control / controller

9AEI-406.71 41

E Voltage Primary element (sensor)

-

F Flow rate/ Flow - -

G GagingGlass, viewing

device -

H Hand (manually Initiated) - -

I CurrentIndicate/ Indicator /

Indicating -

D Density or specific gravity

- -

9AEI-406.71 42

J Power - -

K Time - control Station

L Level Light -

M Moisture - -

N User's choice User 's choice User's choice

O User's choice Orifice / Restriction -

P Pressure or

vacuum Point / Test connection

-

Q Quantity - -

9AEI-406.71 43

R

Radiation/Ratio /

Radioactivity

Record/Recording/Recorder

-

S Speed or

frequency - Switch

T Temperature -Transmit /

Transmitter / Transmitting

U Multivariable Multifunction -

9AEI-406.71 44

V Vibration / Viscosity Valve/ Damper -

W Weight, Force Well -

YEvent

/State/PresenceRelay /compute/

convert-

Z Position, DimensionDriver, Actuator,

(Final Control Element)

9AEI-406.71 45

EXAMPLES

S.NO TAG NAME NAME OF THE INSTRUMENT

1 PA PRESSURE ALARM

2 SR SPEED RECORDER

3 FE FLOW SENSOR

4 TI TEMPERATURE INDICATOR

5 TW TEMPERATRE WELL

6 FT FLOW TRANSMITTER

9AEI-406.71 46

S.NO TAG NAME NAME OF THE INSTRUMENT

1 PIC PRESSURE INDICATING CONTROLER

2 HCV HAND CONTROLLED VALVE

3 PCV PRESSURE CONTROL VALVE

Note: Generally the second letter represents read out /

passive function followed by out put function letter. But the

exception is that the output letter C (control) precedes the

out put letter V (valve)

E.g.. HCV, PCV

9AEI-406.7247

9AEI-406.7248

• The Indian standards Institution (ISI) was set up in 1947

after independence as a registered society under a Govt

of India resolution .

• Due to fast changing socio-economic scenario Govt

recognized the need for strengthening the activities of ISI

and changed the name as BIS (Bureau of Indian

standards) on 1st April 1987

History

9AEI-406.7249

Objectives of Bureau of Indian Standards

• Development of standardization, marking and quality

certification (By checking incoming raw material and

outgoing finished products at different levels of

production)

• To provide new thrust to standardization and quality

Control

9AEI-406.7250

Objectives of Bureau of Indian Standards…

• To evolve a national strategy for according recognition to

standards and integrating them with growth and development of

production and exports.

9AEI-406.7251

• In BIS the ISI mark gives guarantee to the purchaser that

the goods with this mark have been manufactured under a

well defined system of quality control.

Importance

9AEI-406.7252

Some of BIS standards

• IS QC 440000: 1994

Thermistors –General specifications

• IS 12762 : Part1 : 1989

Measurement of photovoltaic current voltage

Characteristics

9AEI-406.7253

• IS 6804 : 1972

Glass electrodes for direct reading PH meters

• IS 7358 : 1984

Specifications for thermocouple

Some of BIS standards cont….

9AEI 504.7354

9AEI 504.7355

American National Standard Institute (ANSI)

• American National Standard Institute abbreviated as ANSI

• It is a private non profit organization.

• It oversees the development of standards for products,

processes, systems & personnel in the united states.

9AEI 504.7357

ANSI Membership Comprises of

• Govt offices

• Organizations

• Corporations

• Academic & international bodies & Individuals

9AEI 504.7358

• The institute represents the interest of more than

1,25,000 companies & 3.5 million professionals.

• ANSI actively engaged in programmes like

ISO 9000 ( Quality )

ISO 14,000 ( Environment )

9AEI 504.7359

• ANSI is the official U.S representative to International

Organisation for Standardisation (ISO) International

Electrotechnical Commission (IEC).

• ANSI is also member of the International Accreditation Forum

(IAF).

9AEI 504.7360

Document No Document File

C37.1-1994 IEEE standard definition, specification &analysis of systems used for supervisory control, Data Acquisition &

automatic control

C39.4-1966 Specification for Automatic Null balancing Electrical measuring Instruments

C42.100-1972 Directory of Electrical & Electronics

C39.2-1964 Direct Acting Electrical Recording Instruments

Publications of ANSI

9AEI-504.7461

British Standard Institution

• British Standard Institution abbreviated as BSI

• It is worlds first national standard organization

• It serves the interest of a wide range of industry sectors

as well as governments ,consumers, employees and

society

9AEI-504.7462

• British standard is the UK’s National standards Body (NSB).

• There are over 27,000 current British Standards available.

• Every year nearly 1700 standards are revised or newly

developed by BSI.

• BSI is raising standard over 100 countries world wide.

9AEI-504.7463

9AEI-504.7464

BSI provides the following Standards also:

• ISO 9001(Quality)

• ISO 14001(Environmental )

• OHSA5 18001(Occupational Health &Safety )

9AEI-504.7465

• BSEN 60584-3 : 2008

Thermocouples (extension & compensating cables).

• BSEN 60770-1

Transmitters for use in industrial process control system.

Some of the standards of BSI:

9AEI-504.7566

• ISA is an organization of engineers, technicians & others

who work in the field of Instrumentation, measurement&

control of Industrial Processes.

• ISA is a non profit organization that helps its 30,000

world wide members to solve difficult technical problems.

• It was founded in 1945

Instrumentation system & Automation society

9AEI-504.7567

9AEI-504.7568

Instrumentation, system & Automation society

• ISA

• Develops Standards

• Certify industry professionals

• Provides Education & Training

• Publishes books & Technical Articles

9AEI-504.7569

• ISA involves in

• Design

• Development

• Production & Application of Devices

9AEI-504.7570

S.no. Name of the standard

Description

01 ISA-5.1 Instrumentation symbols & Identification

02 ISA-5.3 Graphic symbols for distributed control

03 ISA-5.4 Instrument loop diagram

04 ISA-5.5 Graphic symbols for process display

05 ISA-5.20 Standards for Industrial Automation & control

06 ISA-75 Control valve standards

Some of the Standards of ISA

9AEI-504.7571

DIN

• DIN; in English, the German Institute for Standardization

is the German national organization for standardization

and is that country's ISO member body.

9AEI-504.7572

9AEI-504.7573

• DIN is a registered association founded in 1917,

originally as Normenausschuss der deutschen Industries

(NADI, Standardization Committee of German Industry).

• In 1926 the NADI was renamed Deutscher

Normenausschuss (DNA, German Standardization

Committee) in order to indicate that standardization now

covered many fields, not just industrial products.

9AEI-504.7574

• In 1975 the DNA was finally renamed DIN.

• Its headquarters is in Berlin.

• Since 1975 it has been recognized by the German

government as the national standards body and

represents German interests at international and

European level.

9AEI-504.7575

List of DIN standards

• DIN 476: international paper sizes (now ISO 216 or DIN EN ISO 216).

• DIN 946: Determination of coefficient of friction of bolt/nut assemblies under specified conditions.

• DIN 1451: typeface used by German railways and on traffic signs.

• DIN 31635: transliteration of the Arabic language.

• DIN 72552: electric terminal numbers in automobiles.