“PRACTICAL INSIGHTS ON CONTROL & INSTRUMENTATION,



SYMBOLS & STANDARDS

1) INSTRUMENT ABBREVIATIONS

PRESSURE

P : PRESSURE

PI : PRESSURE INDICATOR

PG : PRESSURE GAUGE

PCV : PRESSURE CONTROL VALVE

PT : PRESSURE TRANSMITTER

PIT : PRESSURE INDICATING TRANSMITTER

PIC : PRESSURE INDICATING CONTROLLER

PDT : PRESSURE DIFFERENTIAL TRANSMITTER

PRV : PRESSURE REDUCING VALVE

PSV : PRESSURE SAFETY VALVE

PS : PRESSURE SWITCH

PSH : PRESSURE SWITCH HIGH

PSL : PRESSURE SWITCH LOW

PSHH : PRESSURE SWITCH HIGH HIGH

PSLL : PRESSURE SWITCH LOW LOW

PDS : PRESSURE DIFFERENTIAL SWITCH

PDSH : PRESSURE DIFFERENTIAL SWITCH HIGH

PDSL : PRESSURE DIFFERENTIAL SWITCH LOW

PA : PRESSURE ALARM

TEMPERATURE

T : TEMPERATURE

TI : TEMPERATURE INDICATOR

TW : THERMOWELL

TM : THERMOMETER

TE : TEMPERATURE ELEMENT

RTD : RESISTANCE TEMPERATURE DETECTOR

T/C : THERMOCOUPLE

TT : TEMPERATURE TRANSMITTER

TIC : TEMPERATURE INDICATING CONTROLLER

TRC : TEMPERATURE RECORDER CONTROLLER

TCV : TEMPERATURE CONTROL VALVE

TS : TEMPERATURE SWITCH

TSH : TEMPERATURE SWITCH HIGH

TSL : TEMPERATURE SWITCH LOW

TA : TEMPERATURE ALARM

FLOW

F : FLOW

FI : FLOW INDICATOR

FG : FLOW GLASS / FLOW GAUGE

FE : FLOW ELEMENT

FIT : FLOW INDICATING TRANSMITTER

FCV : FLOW CONTROL VALVE

FIC : FLOW INDICATING CONTROLLER

FS : FLOW SWITCH

FY : FLOW CONVERTER

FA : FLOW ALARM

FR : FLOW RECORDER

FRC : FLOW RECORDING CONTROLLER

LEVEL

L : LEVEL

LI : LEVEL INDICATOR

LG : LEVEL GAUGE

LIT : LEVEL INDICATING TRANSMITTER

LCV : LEVEL CONTROL VALVE

LDT : LEVEL DISPLACER TRANSMITTER

LIC : LEVEL INDICATING CONTROLLER

LRC : LEVEL RECORDING CONTROLLER

LS : LEVEL SWITCH

LSH : LEVEL SWITCH HIGH

LSL : LEVEL SWITCH LOW

LA : LEVEL ALARM

RLT : RADAR LEVEL TRANSMITTER

GENERAL

DCS : DISTRIBUTED CONTROL SYSTEM

SCADA : SUPERVISORY CONTROL AND DATA ACQUISITION SYSTEM

PLC : PROGRAMMABLE LOGIC CONTROLLER

HART : HIGHWAY ADDRESSABLE REMOTE TRANSDUCER

HHT : HAND HELD TERMINAL

SFC : SMART FIELD CONFIGURATOR

ESD : EMERGENCY SHUT DOWN

AOV : AIR OPERATED VALVE

MOV : MOTOR OPERATED VALVE

SV : SOLENOID VALVE

XVE : VIBRATION PROXIMITOR

XVT : VIBRATION TRANSMITTER

AE : ANALYZER

JB : JUNCTION BOX

ILD : INSTRUMENT LOOP DIAGRAM

P&ID : PIPING AND INSTRUMENT DIAGRAM

IIS : INSTRUMENT INSTALLATION SCHEDULE

TDR : TIME DELAY RELAY

SP : SET POINT

NC : NORMALLY CLOSED

NO : NORMALLY OPEN

MCC : MOTOR CONTROL CENTRE

IAS : INSTRUMENT AIR SUPPLY

IGS : INSTRUMENT GAS SUPPLY

ACFO : AIR TO CLOSE FAIL OPEN

AOFC : AIR TO OPEN FAIL CLOSE

FFA : FLAME FAILURE ALARM

P/I – P to I : PNEUMATIC TO CURRENT CONVERTER

I/P – I to P : CURRENT TO PNEUMATIC CONVERTER

PB : PUSH BUTTON

PID : PROPORTIONAL, INTEGRAL AND DERIVATIVE

E/H : ELECTRO HYDRAULIC ACTUATOR

BOV : BLOW DOWN VALVE

A/M : AUTO / MANUAL – 2 POSITION SWITCH

ZS : POSITION SWITCH

HS : HAND SWITCH

2) INSTRUMENT LINE SYMBOLS

2.1) INSTRUMENT SUPPLY or CONNECTION TO PROCESS ___________________

2.2) PNEUMATIC SIGNAL ___________________

2.3) ELECTRICAL SIGNAL (ANALOG SIGNAL) (mA DC (OR) VDC) ------------------------

3.4) ELECTROMAGNETIC or SONIC SIGNAL ___________________

3.5) HYDRAULIC SIGNAL ___________________

2.6) CAPILLARY TUBE (FILLED SYSTEM) ___________________

2.7) PULSE TRAIN _ _ _ _ _ _ _

2.8) INTERNAL SYSTEM LINK (SOFTWARE or DATA LINK)

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3) TYPES OF SUPPLY

3.1) AS - AIR SUPPLY IA – INSTRUMENT AIR

PA – PLANT AIR

3.2) ES – ELECTRICAL SUPPLY

3.3) GS – GAS SUPPLY

3.4) HS – HYDRAULIC SUPPLY

3.5) NS – NITROGEN SUPPLY

3.6) SS – STEAM SUPPLY

3.7) WS – WATER SUPPLY

The “ES” or “AS” symbol is to be used only for Field Devices requiring supply. For panel mounted instruments power supplies are not shown on flow sheet.

4) GENERAL INSTRUMENT SYMBOLS

5) IDENTIFICATION LETTERS

TABLE – 1

|  |FIRST LETTER (4) |SUCCEEDING LETTER (3) |

| |MEASURED / INITIATING VARIABLE |MODIFIER |READOUT / PASSIVE FUNCTION |OUTPUT FUNCTION |MODIFIER |

|A |ANALYSIS (5, 19) | |ALARM | | |

|B |BURNER, COMBUSTION | |USER’S CHOICE (1) |USER’S CHOICE (1) |USER’S CHOICE (1) |

|C |USER’S CHOICE (1) | | |CONTROL (13) | |

|D |USER’S CHOICE (1) |DIFFERENTIAL (4) | | | |

|E |VOLTAGE | |SENSOR (PRIMARY ELEMENT) | | |

|F |FLOW RATE |RATIO (FRACTION) (4) | | | |

|G |USER’S CHOICE (1) | |GLASS, VIEWING DEVICE (9) | | |

|H |HAND | | | |HIGH (7,15,16) |

|I |CURRENT (ELECTRICAL) | |INDICATE (10) | | |

|J |POWER |SCAN (7) | | | |

|K |TIME, TIME SCHEDULE |TIME, RATE OF CHANGE (4,| |CONTROL STATION (22) | |

| | |21) | | | |

|L |LEVEL | |LIGHT (11) | |LOW (7, 15, 16) |

|M |USER’S CHOICE (1) |MOMENTARY (4) | | |MIDDLE, INTERMEDIATE (7, 15) |

|N |USER’S CHOICE (1) | |USER’S CHOICE (1) |USER’S CHOICE (1) |USER’S CHOICE (1) |

|O |USER’S CHOICE (1) | |ORIFICE, RESTRICTION | | |

|P |PRESSURE, VACUUM | |POINT (TEST) CONNECTION | | |

|Q |QUANTITY |INTEGRATE, TOTALIZE (4) | | | |

|R |RADIATION | |RECORD (17) | | |

|S |SPEED, FREQUENCY |SAFETY (8) | |SWITCH (13) | |

|T |TEMPERATURE | | |TRANSMIT (18) | |

|U |MULTIVARIABLE (6) | |MULTIFUNCTION (12) |MULTIFUNCTION (12) |MULTIFUNCTION (12) |

|V |VIBRATION, MECHANICAL ANALYSIS (19) | | |VALVE, DAMPER, LOUVER (13) | |

|W |WEIGHT, FORCE | |WELL | | |

|X |UNCLASSIFIED (2) |X AXIS |UNCLASSIFIED (2) |UNCLASSIFIED (2) |UNCLASSIFIED (2) |

|Y |EVENT, STATE / PRESENCE (20) |Y AXIS | |RELAY, COMPUTE, | |

| | | | |CONVERT(13,14,18) | |

|Z |POSITION, DIMENSION |Z AXIS | |DRIVER, ACTUATOR, UNCLASSIFIED| |

| | | | |FINAL CONTROL ELEMENT | |

NOTE: Numbers in parentheses refer to specific explanatory notes.

6) TYPICAL LETTER COMBINATIONS

TABLE – 2

7) FUNCTIONAL BLOCKS – FUNCTIONAL DESIGNATIONS

THE FUNCTION DESIGNATIONS ASSOCIATED WITH CONTROLLERS, COMPUTING DEVICES, CONVERTERS AND RELAYS MAY BE USED INDIVIDUALLY OR IN COMBINATION (ALSO SEE TABLE 1, NOTE 14). THE USE OF A BOX AVOIDS CONFUSION BY SETTING OFF THE SYMBOL FROM OTHER MARKINGS ON A DIAGRAM AND PERMITS THE FUNCTION TO BE USED AS A STAND ALONE BLOCK ON CONCEPTUAL DESIGNS.

TABLE -3

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8. APPLICATION EXERCISE

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IAS 130 kPa

Options

ES 24 V DC

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