P and IDs.ppt

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PART 1

P&ID TAG NUMBER

LETTERS & NUMBERS

• Letters & numbers are placed inside general piping and instrumentation diagram (P & ID) symbols called tag numbers,

• These letters and numbers provide useful information about each instrument.

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• The letters, called functional identifiers, are located in the top portion of the symbol.

• The sequence of letters designates the instrument's function.

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• The first letter indicates the types of the process variables where:P = Pressure T = TemperatureF = Flow L = Level

• When a symbol contains two letters, the second letter indicates the function of the instrument such as:R = Recorder C = ControllingT = Transmitter I = Indicator

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• If a symbol has three or four letters, the second letter provides information about the first letter. For example, if PDAH is used, the letters represent:

• Differential Pressure Alarm that is activated when the pressure is too High.P = PressureD = DifferentialA = AlarmH = High

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• Numbers called loop identifiers, located in the bottom half of the symbol.

• A loop identifier shows the loop in which the instrument is located.

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• This table gives information about each letter of the functional identifier based on its location in the sequence.

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TEST 1

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NOW,TEST YOURSELF

QUESTION 1

Q1: P&ID numbers consist of __________ .

A. NumbersB. LettersC. Both A & B

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QUESTION 2

Q2: Functional identifiers are located at the __________ of the P&ID symbol. They indicate the __________ of the instrument.

A. TopB. BottomC. FunctionD. Location

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QUESTION 3

Q3: if a functional identifier has three letters, the second letter __________.

A. Tells the function of the instrumentB. Provide information about the first

letterC. Indicates the type of process variable

being controlled by the controller

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QUESTION 4

Q 4: The number in the symbol indicates the __________ .

A. Address of the instrumentB. Loop where the instrument is locatedC. Location of another instrument that this instrument controls

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PART 2

LINE SYMBOLS

• Lines connect the symbols in a piping and instrumentation diagram (P&ID).

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• Each line represents the physical connection between the instruments in a process control system.

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• On the P&ID, different types of lines are used to indicate specifically what is passed along the connection from one instrument to the next.

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• The different types of line symbols used in a P&ID are shown with their used:

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TEST 2

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NOW,TEST YOURSELF

QUESTION 1

Q1: Click on each symbol and drag it to the type of line it represents:

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PART 3

P&ID GENERAL INSTRUMENT SYMBOLS

• On a process control diagram, a circle, called a balloon, is used to indicate an instrument.

• The balloon symbol may also have lines that indicate the instrument’s location and function.

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• A balloon by itself indicates a discrete stand-alone instrument, such as a:TransmitterSensorAlarm

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• If the balloon is inside a square,the instrument is identified asa shared device.

• This means that in additionto performing its specificfunction, the instrumentdisplays or controls theprocess variable.

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• If a hexagon is used instead of a balloon, a computer function is indicated.

• A diamond inside a square identifies a programmable logic controller.

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• Horizontal lines, which run through the symbols and divide them in half, or an absence of lines indicates:– At the point of measurement.– Near the final control element.

• Symbols without horizontal lines indicate the instrument is installed in the field, either:– How the instrument is mounted.– Where it is located.

• Symbols with a single line indicatethe instrument is mounted on a boardin the control room, making itaccessible to the operator or for routine maintenance.

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• Double lines indicatethe instrument is atan auxiliary location away from the process.

• Symbols with a singledashed line indicatethe instrument islocated behind a paneland not easilyaccessible.

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TEST 3

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NOW,TEST YOURSELF

QUESTION 1

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QUESTION 2

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QUESTION 3

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QUESTION 4• Click on each symbol and drag it to the correct location

on the table:

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• The answer is:

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PART 4

READING A P&ID LOOP

• P&ID drawings provide various types of information, such as:– Which components are in a circuit,– How instruments are connected,– Where instruments are located,– What functions the instruments perform.

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• A through understanding of these diagrams helps the operator or technician to do three things:– Monitor a process,– Work more efficiently,– Troubleshoot.

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• To illustrate how to read a P&ID diagram, a single loop that controls a heat exchanger is used.

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• In this system, steam is fed by a pipe into a sealed enclosure (called a heat exchanger) through which water flows.

• As the passes through the enclosure & makes contact with the pipe, the water is heated to a higher temperature.

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• The symbol that looks like a bow tie represents a valve that passes fluid.

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STEPS OF READING P&ID DIAGRAM:

STEP 1:The tag number 401 on the components indicates they are located on the control loop identified by that number.

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STEP 2:The first letter of each functional identifier is a “ T “, which means temperature is being controlled.

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STEP 3:The instrument connected to the heat exchanger provides two different types of information.- The second letter in the functional identifier indicates it is a transmitter.- The balloon has no line inside its symbol, which means it is field mounted.

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STEP 4:The line with Xs indicates a capillary tube sends a signal from the exchanger to the transmitter.

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STEP 5:The dashed line from the transmitter indicates it produces an electronic signal.

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STEP 6:The instrument to which the transmitter sends an electronic signal is a controller & indicator, specified by second & third letters, “ IC “ of the functional identifier.

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STEP 7:The solid line inside the balloon indicates it is board mounted.

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STEP 8:The dashed line to the left of the controller indicates it sends an electronic signal.

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STEP 9:The instrument to which the controller output is connected is a transducer, as indicated by the second letter,“ Y “, of the functional identifier inside the balloon.

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STEP 10:The function of the transducer is converting an electronic signal to a pressure signal, as specified by the square containing the letters “ I/P “.

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STEP 11:The fine line with diagonal markings that extends from the bottom of the transducer symbol is a pneumatic line.

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STEP 12:The half circle symbol represents a pneumatic-controlled (diaphragm) actuator. Its function is to open & close the globe valve that regulates the steam that flows to the heat exchanger.

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STEP 13:The arrow that points downward from the actuator indicates it is a “fail-to-close” type of valve.

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REVIEW:

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TEST 4

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NOW,TEST YOURSELF

QUESTION 1

Q1: Read the below P&ID?

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THE END

E/I MAINTENANCE DEPT.ANALYZER SECTIONDONE BY: MOHAMAD AL-SULTANSABIC-SAFCO

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P and IDs.ppt

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