asad report final

INSTRUMENTATION DEPARTMENT
F A S T - N A T I O N A L U N I V E R S I T Y K A R A C H I Page 1
INTERNSHIP REPORT
(INSTRUMENTATION DEPARTMENT)
JULY 17- AUGUST20, 2014
SUBMITTEDTO:
UmairAleem (assistantmanager,instrumentation)
SUBMITTEDBY:
Asad Nauman
Bachelorsof Science in Electrical Engineering
FAST- NationalUniversityof computerand emerging science,Karachi

Acknowledgment
First of all thanks to ALMIGHTY ALLAH for granting me such a valuable chance of internship
at LOTTE CHEMICAL PAKISTAN. I would like to thank HUMAN RESOURCE
DEPARTMENT for selecting me to be the part of this organization. Special thanks to MR
UMAIR ALEEM for enlightening me with a complete insight of Instrumentation department in
very friendly environment and assigning me the tasks which were rich in learning. Thanks to MR
MUSHAHAR whose guidelines and assistance I acquired from him was undoubtedly provided
with sincere dedication.
I would like to thank Mr.Amir Azam, Mr. Hassan Shahid, Mr. Nadeem Bhatti, Mr. Umer Zareen
Khan, Mr. Muhammad Asif Farooqi and Mr. Syed Mahmood Ali for providing me with
continuous productive knowledge and refining my concepts in parallel. Lastly, I would like to
thank my companions who accompanied me on this internship.
My internship at Lotte was a wholesome learning experience. I look forward to working with the
Lotte in the future.

PREFACE
This report is intended to give the reader an insightful account of all theoretical and empirical
learning experiences during an internship program at Lotte Chemical Pakistan LTD. It serves to
teach and elaborate each engineering principle experienced during this period in elaborative
content and briefly discusses pre-requisite technical knowledge of Electrical Engineering
courses.
It would be unwise to claim that this report is a complete and exhaustive account of all
Instrument related operations, procedures and equipment at LCPL. It actually reflects of what, I,
as an Electrical Engineering Intern studied and learned at LCPL during a one-month internship
program.
My four weeks internship at LOTTE CHEMICALS PAKISTAN provided me the essence to
utilize my theoretical knowledge.

TABLE OF CONTENTS
ABOUT LOTTE CHEMICAL PAKISTAN .........................................................................................7
SAFETY HEALTH & ENVIRONMENT.............................................................................................8
EMPLOYEE’S SAFETY:...............................................................................................................8
EXTRA SAFETY:..........................................................................................................................8
OVERVIEW OFPLANT....................................................................................................................9
CORE AREA.................................................................................................................................9
 OXIDATION PLANT (Ox)..................................................................................................9
 PURIFICATION .................................................................................................................9
PTA CHEMICAL PROCESS.....................................................................................................10
NON-CORE AREAS....................................................................................................................10
UTILITIES...............................................................................................................................10
PRESSURE.....................................................................................................................................12
 ABSOLUTEPRESSURE:..................................................................................................13
 GAUGE PRESSURE:........................................................................................................13
 VACUMM PRESSURE:....................................................................................................13
PRESSURE MEASURING ELEMENTS:......................................................................................13
 BOURDON TUBE............................................................................................................13
 BELLOWS........................................................................................................................15
 DIAPHARGM...................................................................................................................15
PRESSURE TRANSDUCERS...................................................................................................17
TEMPERATURE.............................................................................................................................17
INDICATING TEMPERATURE MEASURING DEVICES............................................................17
1. EXPANSION THERMOMETERS:....................................................................................17
2. BIMETALLIC STRIP........................................................................................................18
ELECTRICAL TEMPERATURE MEASURING DEVICES ..........................................................................19
 THERMOCOUPLE:..........................................................................................................19
 RESISTANCE TEMPERATURE DETECTORs (RTDs) .....................................................20
FLOW MEASUREMENT................................................................................................................22
TYPES OF FLOW METER..........................................................................................................23
 HEAD FLOW METER:.........................................................................................................23

 ORIFICE PLATE..............................................................................................................23
 VENTURI TUBE:.............................................................................................................24
 FLOW NOZZEL...............................................................................................................24
 ROTAMETER......................................................................................................................25
 TURBINE METER:..............................................................................................................26
 VORTEX FLOW METER:....................................................................................................26
 ELECTROMAGNETIC FLOW METER................................................................................28
 CORIOLIS METER..............................................................................................................28
LEVEL MEASUREMENT...............................................................................................................29
 DISPLACEMENT (BUOYANCY):........................................................................................30
 CAPACITANCE:..................................................................................................................30
 RADIO-ACTIVE METHOD:.................................................................................................31
 ULTRA-SONIC METHOD:...................................................................................................32
 BUBBLER METHOD:..........................................................................................................32
 DIFFERENTIALPRESSURE METHOD...............................................................................33
DENSITY MEASUREMENT...........................................................................................................33
 MASS FLOW METER..........................................................................................................34
 RADIOACTIVE METHOD...................................................................................................34
 pH ANALYZER...................................................................................................................35
 CONDUCTIVITY ANALYZER............................................................................................36
 OXYGEN ANALYZER ........................................................................................................37
 CARBON DIOXIDE ANALYZER ........................................................................................38
TYPES OF CONTROL VALVES.................................................................................................39
 GLOBE VALVE...................................................................................................................39
 GATE VALVE.....................................................................................................................40
 BALL VALVE:.....................................................................................................................40
 BUTTERFLY VALVE..........................................................................................................40
 ANGLE VALVE:..................................................................................................................41
FLOW CHARACTERISTICS....................................................................................................41
CONTROL VALVE AUXILIARY ............................................................................................42
DISTRIBUTED CONTROL SYSTEM (DCS) ...................................................................................43

DCS AT LCPL.............................................................................................................................44
WORKING OF DELTAV.............................................................................................................44
PROGRAMMABLE LOGIC CONTROLLER (PLC) .........................................................................44
COMPONENTS OF PLC..............................................................................................................45
PLC OPERATING CYCLE...........................................................................................................46
PROGRAMMING LANGUAGES OF PLC ...................................................................................46
 LADDER LOGIC..............................................................................................................46
 FUNCTIONAL BLOCK DIAGRAM (FBD).......................................................................47
FIRE/GAS & PA SYSTEM...............................................................................................................48
FIRE AND GAS SYSTEM...........................................................................................................48
 MAIN FIREPANEL (FD001/FD002):................................................................................48
 MIMIC PANEL:................................................................................................................48
 FIELD EQUIPMENTS:.....................................................................................................49
 SATELLITE FIRE PANELS:.............................................................................................49
 FIRE SPRINKLER SYSTEM:............................................................................................49
 FM200:.............................................................................................................................49
CO-GENERATION (CO-GEN)........................................................................................................49
ASSIGNMENTS..............................................................................................................................52

ABOUT LOTTE CHEMICAL PAKISTAN
Lotte Chemical Pakistan Ltd is a supplier of Purified Terephthalic Acid C6H4(COOH)2 (PTA),
an essential raw material for Pakistan’s textile and PET packaging industries and forms the
backbone of the polyester chain, including Polyester Staple Fiber, Filament Yarn and PET (bottle
grade) resin. Lotte is a South Korean multinational, acquired the majority shareholdings in
Pakistan PTA Limited (PPTA) in September 2009. Later, the name of the Company was changed
to Lotte Chemical Pakistan Ltd.
Pakistan PTA Ltd was a member of the ICI Worldwide Group, which was acquired in 2008 by
AKZO Nobel. With effect from 17 September 2009, Lotte completed its acquisition of the
majority shareholdings in Pakistan PTA Limited.
The PTA plant was constructed in 1996/97 and started production in June 1998. Since 2002 the
plant has operated above its nameplate capacity of 400,000 tons per annum and following minor
de-bottlenecking and process improvements, is capable of ramping that up to 500,000 tons per
annum.
There have been three major changes in the plant since its establishment described below as
follows:
 SUPPLEMENTARY PROCESS AIR COMPRESSOR (SPAC) - (2006)
This was for increasing the production rate in the plant.
 CATALYST RECOVERY UNIT (CRU) - (2010)
For optimization LCPL has its CRU, which is use for recovering of catalyst so that it can
be used again in reaction
 GAS TURBINE GENERATOR (GTG) - (2012)
The purpose of GTG is to generate electricity at LCPL.

SAFETY HEALTH & ENVIRONMENT
Lotte Pakistan PTA is a responsible organization keeping great care about the safety and health
of their employees and workers. For this purpose they have one of the best safety, health and
environment (SHE) policy throughout Pakistan.
EMPLOYEE’S SAFETY:
 The main equipment provided to each and every employee includes;
• Safety shoes
• Splash goggles
• LEP (Light Eye Protect)
• Ear plugs.
 The whole plant has certain lined criteria, where these PPE’s are to be used.
• YELLOW lines are for PLANT AREA.
• GREEN and WHITE lines are for GOGGLE AREA.
• RED AND WHITE is the high noise area so it’s for EAR PLUGS.
• Parallel RED & GREEN lines are for HAZARDOUS AREA.
EXTRA SAFETY:
• Smoking is not allowed in any area, particular area is allocated for smoking.
• No battery-operated device is allowed in the plant area like mobile, radio, torch,
Camera, Calculator etc, as it may cause ignition because a slight spark could cause fire.
• Assembly points are established for employees in case of fire conditions.
• Toxic refuges are there.

OVERVIEW OF PLANT
The PTA plant is divided into two areas:
CORE AREA
 OXIDATION PLANT (Ox)
Paraxylene, acetic acid, and catalyst (Cobalt Manganese Bromide), are mixed to create a feed
which goes to the oxygen reactor to react with compressed air (18 bar). The major proportion of
Terephthalic Acid produced is precipitated to form slurry in the reactor. This slurry is then
passed through crystallizers where it is cooled to form crystals. It then goes to the ROVAC
(Rotary Vacuum Filter), where it is filtered. After filtering the product, it is dried in the dryer to
produce Crude Terephthalic Acid (CTA). The residue is treated in Catalyst Recovery Unit
(CRU) to recover acetic acid for reusing it in the reaction. The waste water is sent to Effluent
Treatment Plant (ETP).
.
PX + O2 CTA
 PURIFICATION
In PURE the CTA which contains few impurities is purified, resulting in PTA which is 99.98%
pure product. The most problematic impurity is 4-formylbenzoic acid (commonly known in the
field as 4-carboxybenzaldehyde or 4-CBA), which is removed by hydrogenation of a hot aqueous
solution of Terephthalic acid. This solution is then passed to the crystallizers where it is cooled
to crystallize. Next it passes through the PTA drier where it is dried to yield the final product,
Purified Terephthalic Acid (PTA).
CTA + H2 PTA
CATALYST + SOLVENT
CATALYST+SOLVENT

PTA CHEMICAL PROCESS
NON-CORE AREAS
UTILITIES
Utilities plant facilitates core plant by providing services to it such as
 Raw material storage system
 Raw material pumping station
 Effluent treatment plant (ETP)
 Instrument air compressor
 Base load generator
 Emergency diesel generator
 Boilers
 Reverse osmosis plant
 Cooling tower
Utilities also provide raw material used in the production of PTA, which are as follow:
 Paraxylene
 Acetic acid
 Catalyst (cobalt manganese bromide)
 Caustic acid
 Demine water
 Co-generation plant

INSTRUMENT SYMBOLS
ELD’S AND ILD’S
Engineering Line Diagram

PRESSURE
Pressure is the amount of force applied on a unit of area. It is possible to determine the pressure
exerted by solids, liquids, and gases by determining the force they exert over a given area. It’s
formula is
𝑃 = 𝐹/𝐴
F= Force
P= Pressure
A= Area
UNITS OF PRESSURE:
 Pounds per square inch or psi
 Pascal
 Newton per meter square
 Inches of water
 Inches of mercury
PRESSURE MEASURMENT SCALES:
There are two kinds of pressure scales most commonly used for pressure measurement.
1. Absolute scale: The absolute scale is used to measure absolute pressures. Since absolute
scale does not take atmospheric pressure into account, all measurements on the absolute
scale are referenced to “Theoretical zero”. Absolute scale are written in units of PSIA.

2. Gauge scale: The gauge scale is used to measure gauge pressure. The gauge scale does
take into account the atmospheric pressure. Gauge scale are written in units of PSIG.
There are three types of pressure,
 ABSOLUTE PRESSURE:
Pressure measured relative to an absolute vacuum (absolute zero pressure).
Absolute pressure= gauge pressure + atmospheric pressure
 GAUGE PRESSURE:
Pressure greater than atmospheric pressure that is measured relative to atmospheric
pressure.
Gauge pressure= absolute pressure - atmospheric pressure
 VACUMM PRESSURE:
Pressure less than atmospheric pressure that are measured relative to atmospheric
pressure.
Vacuum pressure = Atmospheric pressure – Absolute pressure
PRESSURE MEASURING ELEMENTS:
Many of the pressure measuring instruments contain devices called pressure elements. They senses
changes in pressure and convert the changes into mechanical motion. The most common pressure
elementsare the following:
 Bourdon metallic devices
 Bellows
 Diaphragm
 BOURDON TUBE
Bourdon tube measuring elements are used to measure wide range of pressure. They are
made of many materials like bronze, brass and stainless steel. They are used to measure
very small pressures and vacuum.
Bourdon tube comes in the following different shapes.
 “C” SHAPED BOURDON TUBE:

The tube consists of oval, thin walled metal, one end of which is open while the other end is
closed, called the tip. Depending on the pressure exerted on the bourdon tube the tip moves as
tube straightens out or in. The tip travels relatively small distance.
 SPIRAL BOURDON TUBE:
The basic construction is similar to that of C-type but the tube in this case is wound in spiral. The main
purpose of spiral tube isthat the tiptravel greaterdistance thanthe C-type.
 HELICAL BOURDON TUBE:
In helical bourdon tube the coil are arranged over each other. Due to this reason they are
more compact than C-type and spiral tube.

 BELLOWS
The bellows is a cylindrical, thin walled, metal tube, one end of which is open while the
other end is closed. Pressure is applied to the open end and is indicated at the closed end.
The spring within the bellows is used as opposing spring to control the motion of the tip
of the bellows.
 DIAPHARGM
To measure and indicate very small changes in pressure, an instrument is designed which
is known as Diaphragm. There are mainly two types of diaphragms given below.
• METALLIC DIAPHRAGM:
It consists of two circular cupped shaped thin metal joined together to form a saucer
shaped capsule. The pressure connection is taken from the top of the capsule. When
pressure is applied to capsule, the pressure causes the capsule to bulge or flex and the
movement is detected by the sensitive instruments mechanism that are attached to the
diaphragm assembly.
STACK METALLIC DIAPHRAGM
The basic construction of the diaphragms are same but the main difference is that in stack
metallic diaphragm there are three to four capsules stacked above each other. The main

advantage is that there is three to four time’s greater movement of the indicator on the top
of the capsule.
 LIMP OR SLACK DIAPHRAGMS:
Limp or slack diaphragm has an additional part to operate: an opposing spring. The opposing
spring forces the element to return to its original position after the source is removed.

PRESSURE TRANSDUCERS
A transducer is device that receives one form of energy and converts it into another form of
energy, particularly to electrical energy. For example transducer receives pressure as one form of
energy and converts it into current, voltage, or pneumatic signal.
TEMPERATURE
Temperature is one of the basic process variable. Therefore, temperature measurement is
essential to the proper operation of any plant. Both mechanical and electrical instruments are
used to monitor temperature levels. Nowadays the most common methods of measuring
temperature in industry are RTDs and Thermocouples. These along with the other methods are
given below.
℉ = (9
5⁄ ∗ ℃) + 32
°𝐾 = ℃ + 273
℃ = (℉ − 32) ∗ 5
9⁄
INDICATING TEMPERATURE MEASURING DEVICES
1. EXPANSION THERMOMETERS:
Expansion type thermometers operate on the principle that the expansion of liquids, solids, and
gaseshave knownrelationwithtemperature change.

 LIQUID –IN-GLASS THERMOMETER:
These type of thermometers are the oldest and most widely used thermometers. It has a
bulb and a very fine-bore capillary tube. The tube contains alcohol or some other liquid
that expand or contracts with the changes in temperature. The space above the liquid
level is vacuum or this space may be filled with some inert gases, such as nitrogen, argon
etc. Liquid-in-glass thermometer have graduations etched directly on the glass stem.
2. BIMETALLIC STRIP
The essential element in bimetallic expansion thermometer is a bimetallic strip consisting of two
layers of different metals fused together. When this strip is subjected to temperature changes, one
layer expands or contracts more than the other, thus changes the curvature of the strip.
When used as a thermometer, the bimetallic strip is normally wound into a flat spiral, a single
helix, or a multiple helix. Bimetallic thermometers are easily adopted for use as recording
thermometers; a pin is attached to the pointer and positioned so that it marks on a revolving
chart.
3. FILLED-SYSTEM THERMOMETER

Filled-system thermometers are used in locations where the indicating part of the instruments
must be placed some distance away from the point where the temperature is to be measured.
There are basically two types of filled-system thermometers. One type has bourdon tube that
responds primarily to changes in the volume of the filling fluid. The other type has bourdon tube
that responds primarily to changes in the pressure of the filling fluid.
ELECTRICAL TEMPERATURE MEASURING DEVICES
 THERMOCOUPLE:
The basic principle of thermocouple is that if two dissimilar metals are joined together to
form a closed loop and if both the junctions are kept at different temperature, an EMF is
generated and electric current starts flowing in the loop. This effect is called Seebeck
effect. If the temperature of one junction is kept at known value, the temperature of the
other junction can be determined by the amount of voltage produced.

Any two dissimilar metals can be joined together to make a thermocouple. However,
certain metals have been selected over the time that make ideal thermocouples for various
applications. There are several types of these “standard” thermocouples in use today.
 RESISTANCETEMPERATUREDETECTORs(RTDs)
The resistance of the RTDs increases with the temperature in a predictable manner. The
resistance can be calculated by the following formulas.
For small temperature ranges:
𝑅𝑡 = 𝑅𝑜[(1 + 𝛼(𝑇 − 𝑇𝑜)]
For large temperature ranges:
𝑅𝑡 = 𝑅𝑜[(1+ 𝑎𝑡 + 𝑏𝑡2
]
Where “A” and “B” are the coefficients determined by the calibrations.
As the temperature increases around an RTD, the corresponding resistance also
increases. If a known temperature is applied to an RTD, it gives a known resistance value.

The elements of RTD are made of nickel, copper, or platinum. RTDs are passive devices,
needing no more than 1.0 mA to run. RTDs are usually mounted in thermo wells, keeping it
away from physical damages.
 THERMISTORS
Thermistors are also resistance based temperature sensor. Unlike RTDs, the resistance of a
thermistors decrease with increase in the temperature. They have negative temperature
coefficient. Per degree resistance change in a thermistor is much greater than with an RTD, a
thermistor is quite sensitive to minute changes in temperature. Thermistors are used for small
temperature ranges, therefore have not gained popularity of RTDs or even of thermocouples in
industry.
 IC SENSORS
IC temperature sensors are one of the latest innovations in temperature sensing. It uses naturally
linear devices which provides an output that is proportional to absolute temperature. The most
common IC sensor in use today is the AD590 manufactured by Analog Devices. It uses a supply
voltage of between 4 and 30 V. Another popular IC temperature sensor is LM134/234/334 series
from National Semiconductor. The main disadvantage of IC sensors is that it have very limited
temperature range up to 150 C maximum.

 RADIATION SENSORS
All the sensors so far we have discussed have contact with the medium of which the temperature
have to be measured. So they are not so effective where high temperature is needed to be
measure. So the solution to the problem is Radiation sensor that can measure temperature up to
3500° C without any contact with the measured medium. The basic principle of radiation sensor
is that the wavelength of the emitted radiations is determined by the temperature of the target.
The simplest radiation sensor is “Optical Pyrometer”, which simply requires the operator to
match the color of an incandescent target to a color scale in his line of sight.
FLOW MEASUREMENT
FLOW RATE
Flow rate indicates how fast the fluid flowing through the conduit from one place to another.
Flow rate is expressed in the following forms:
Volumetric flow rate: 𝑄𝑣 = 𝐴 ∗ 𝑉
Mass flow rate: 𝑚̇ = 𝑄𝑣 ∗ 𝜌
There are two types of fluid;
TURBULENT FLOW: Type of fluid gas or liquid flow in which the fluid undergoes irregular
fluctuations, or mixing.
LAMINAR FLOW: Type of fluid gas or liquid flow in which the fluid moves in smooth paths
or layers.

TYPES OF FLOW METER
 HEAD FLOW METER:
There are basically two types of head flow meter:
1. The primary element is the restriction in the line.
2. The secondary element is the differential pressure measuring device.
The pressure drop across the meter is proportional to the square of the flow rate.
𝑓𝑙𝑜𝑤 = 𝑅 𝑒 ∗ √∆𝑃
According to Bernoulli’s equation:
Qv1=Qv2
A1*V1=A2*V2
As the area increases the pressure decreases and vice versa.
For the measurement of differential pressure different techniques are used,
 ORIFICE PLATE
Orifice plate is a device used for measuring volumetric flow rate in a pipe. Orifice plate works
based on Bernoulli’s principle. A flat piece of metal with a specific-sized hole bored in it. When
the fluid flows through the orifice in the orifice plate, fluid velocity changes and according to
Bernoulli’s equation pressure also changes. By measuring the difference between pressure values
immediately before and after the orifice plate, volumetric flow can be measured.
There are three different types of orifice plate;
 Concentric: It is used for clean fluid.
 Eccentric: It is used for fluid that also contains moisture.
 Segmental: It is used fluid that contains turbidity.

 VENTURI TUBE:
Venturi tube is a section of pipe with tapered entrance and a straight throat. The venture tube has
a converging conical inlet, a cylindrical throat and a diverging recovery cone. Venturi tubes are
used to handle large flow volumes, low pressure drop, and can be used with most liquids with
solid contents.
At plant venturi tube is installed on boiler feed water line, cooling air to turbine of PAC, HP
steam.
 FLOW NOZZEL
Flow nozzle is an elliptical restriction in the elbow with area for pressure recovery. It is used for
high pressure and temperature steam flows. It can measure approximately 60% higher flow rates
than an orifice plate with same diameter.

 PITOT TUBES AND ANNUBAR
They consists of a tube with openings at the two ends. Small holes in the end positioned so that
one end faces the flowing fluid, while other is opposite to it or at 90 degree. They have minimum
pressure drop across it and can be used for large length.
At plant, Annubars are mostly used on raw water or cooling water line.
 ELBOW TAP METER
As we know that when the liquids flow in circular path, centrifugal force is exerted along the
outer edges, causing changes in the pressure. Short curvature develops more differential pressure
than long curvatures. They are not applicable for low density gases and have low range.
They are installed in plant on Oxidation and CW line mostly.
 ROTAMETER
Variable-area meters, often called Rota meters, consist metal float and a conical glass tube whose
diameter increase with the height. When there is no liquid flow, the float rests freely at the
bottom of the tube. As liquid enters the bottom of the tube, the float begins to rise. The position
of the float varies directly with the flow rate. Its exact position is at the point where the
differential pressure between the upper and lower surfaces balances the weight of the float.
At plant, mostly used where CG is used.

 TURBINE METER:
In turbine meter, a bladed turbine rotor is suspended axially in the direction of flow through the
tube. Each pulse generated represents a discrete amount of volumetric throughput. They have
fast response, good accuracy and high range.
At plant, turbine flow meters are installed on boiler burner fuel gas lines, oil flow to burner line.
 VORTEX FLOW METER:
Vortex shedding meters are velocity meters that can be used to measure the flow rate of fluids
such as steam or gases that may have suspended solids. They have no bearings that can be
damaged by suspended solids.

A vortex shedding meter derives its name from a vortex, which is swirling motion caused by an
object placed in the path of the flowing fluid. A typical vortex shedding meter has an object
called a bluff body placed in the center of the meter in order to create vortices. Bluff bodies are
typically triangular in shape.
As the fluids passes through the edges of the bluff body, vortices are formed. The low pressure
area that is created at the center of each vortex helps to create stress on the bluff body. The
formation of vortex results in low pressure area on one side of the body and low and high
pressure areas results in a differential pressure across the body. This differential pressure creates
a stress on the body, first on one side and then on the other side as the vertex patterns alternate.
There is a sensor which react to the stress; they detect any movement of the bluff body caused by
the vortices. The output of the sensor is usually a small voltage signal, whose frequency is
proportional to the flow rate.
At plant, vortex meters are usually installed on small lines (max 6” line).

 ELECTROMAGNETIC FLOW METER
Electromagnetic flow meters operate on Faraday's law of electromagnetic induction that
states that a voltage will be induced when a conductor moves through a magnetic field.
The liquid serves as the conductor; the magnetic field is created by energized coils
outside the flow tube. The amount of voltage produced is directly proportional to the flow
rate. Two electrodes mounted in the pipe wall detect the voltage, which is measured by
the secondary element.
𝐸 = 𝐾𝐵𝐷𝑉
They have fast responses, good accuracy and easy to install. At plant they are installed
usually at slurry lines.
 CORIOLIS METER
Coriolis meters are true mass meters that measure the mass rate of flow directly as opposed to
volumetric flow. Because mass does not change, the meter is linear without having to be adjusted
for variations in liquid properties. When the tube is moving upward during half of its cycle, the
liquid flowing into the meter resists being forced up by pushing down on the tube. Having been
forced upward, the liquid flowing out of the meter resists having its vertical motion decreased by
pushing up on the tube. This action causes the tube to twist. When the tube is moving downward
during the second half of its vibration cycle, it twists in the opposite direction. The amount of
twist is directly proportional to the mass flow rate of the liquid flowing through the tube.
Magnetic sensors located on each side of the flow tube measure the tube velocities, which
change as the tube twists. The sensors feed this information to the electronics unit, where it is
processed and converted to a voltage proportional to mass flow rate.

 ULTRASONIC METERS
Ultrasonic meters uses Doppler frequency shift of ultrasonic signals. Ultrasonic beam is created
by piezoelectric crystal which is transmitted through the pipe wall in to the fluid at an angle.
Signal reflected back from the flow disturbance is detected by a second piezoelectric crystal.
The frequency shift is proportional to the flow rate. The main advantage of ultrasonic meter is
that there is no contact with the process and are more accurate.
LEVEL MEASUREMENT
Level measurement of process materials are essential in industry, they provide information
necessary to operate industrial process system safely and efficiently.
There are mainlytwotypesof level measurements:
1. Continuous level measurement methods
In some processes one need to know about the level of process continuously at all times
with respect to some reference points.
2. Fixed level detection/point level measurement
In some processes only two points are needed to be measured, that is high and low. When
this is required point to point level measurement technique is used.
 SIGHT GLASS/GLASS GAUGE
It is a transparent vertical tube mounted on the side of the tank. The top and the bottom of
the tube are connected to tank by pipes. They operate on the principle that liquid level
equalize in the containers that are connected together. This means the liquid level visible
in the gauge glass is the same as the level in the tank. A gauge glass is read by viewing
the level of liquid in the tube.

 DISPLACEMENT(BUOYANCY):
The displacer works on the Archimedes Principle which tells that when the displacer is
submerged in liquid, it will lose its weight and this weight loss is proportional to the level of the
liquid. A change in level causes a change in the displacer position due to which the torque tube
assembly rotates and the level is indicated. It can be used for turbulent liquids.
 CAPACITANCE:
In this method a probe is mounted vertically in the vessel. The probe and the wall of the vessel
acts as two plates of the capacitor. As the liquid level rises, capacitance changes and a 4-20 mA
signal at the output is generated and transmitted. Capacitance depends on the area of the plates,
distance between the plates, and the dielectric constant.
𝐶 = ∈ 𝐴
𝑑⁄

When liquid level rises or falls, the capacitance varies due to difference between the dielectric
constants.
 RADIO-ACTIVE METHOD:
A radioactive source is placed at one end and a detector at the other end of the vessel. This
source emits radiations, which are detected by the detector on the other end. When liquid level is
high, very less counts of radiation will detected by the detector and when there is no liquid, the
detector will detect the highest counts of radiation. In this method nothing comes in contact with
the liquid and it is very costly. Cs-137 is used as source and scintillation method is used at
detector.

 ULTRA-SONIC METHOD:
Ultrasonic level sensors work on the principle of sending a sound wave to the contents of
the vessel which is reflected back from the top of the liquid surface. The time it takes for
the reflected wave to return is dependent on the level of liquid.
 BUBBLER METHOD:
The liquid level is determined by measuring the pressure that is applied by the liquid on
the tube. The tube passes air in the liquid, the liquid tries to get into the tube and exerts
pressure. This pressure is called back pressure and is measured by a pressure gauge.
When pressure the high, the level of the liquid is also high. For liquids that react with air,
nitrogen gas can be used in place of air. It is used for corrosive and solid bearing liquids.

 DIFFERENTIALPRESSUREMETHOD
Differential pressure level measurement uses a differential pressure detector which is
installed at the bottom of the open tank. A DP is used to transmit the head pressure that is
sensed by the diaphragm due to the height of the material in the vessel multiplied by a
density variable. The difference in pressure is used to calculate the level of the liquid in
the vessel.
Pressure= head (ft)*specific gravity*0.433 (psi/ft)
There are two arrangements used:
OPEN VESSEL ARRANGEMENT:
The pressure sensed here is difference between vapors space pressure and the total
pressure at the bottom.
CLOSED VESSEL ARRANGEMENT:
Here atmospheric pressure is take as reference for the pressure measurement.
 FLOAT METHOD
It works on the principle of buoyancy, as the fluid level changes, a float will move
correspondingly. A float is usually connected by a flexible tape to a rotating member, in
turn connected to an indicator mechanism.
DENSITY MEASUREMENT
The density or the volumetric mass density, of a substance is its mass per unit volume. The
symbol most often used for density is ρ
𝜌 = 𝑚
𝑉⁄

 MASS FLOW METER
This instrument works on the Coriolis Effect which is the deflection of moving objects
when they viewed in a rotating reference frame. The Coriolis mass flow meter consists of
two U-shaped tubes which are enclosed in an enclosure (usually made of steel) so that the
process fluid does not come out if the tube is broken. These tubes are vibrated constantly
at natural frequency by the drive coils. There are two pick-off coils which measure the
frequency at two ends of the tube as shown in the above figure at left. When there is no
liquid passing through the tubes, the difference in the frequencies of the two ends is zero.
When liquid flows through the tubes there will be a difference in the frequencies, this
difference will be processed by a complex electronic circuit which will result in the
density of the fluid. This instrument can also be used for measuring flow of the liquid.
 RADIOACTIVE METHOD
In this method, a radioactive source is placed at one end and a detector at the other end of
the vessel. This source emits radiations, which are detected by the detector on the other
end. When liquid is dense, very less counts of radiation will be detected by the detector

and when there is clean liquid, the detector will detect the highest counts of radiation. In
this method nothing comes in contact with the liquid and it is very costly.
ANALYTICAL MEASUREMENT
pH Measurements:
One way to measure ion concentration of liquid is in terms of the liquid’s pH. pH is the measure
of hydrogen ion concentration of a solution, which are positively charged particles. Basically, pH
is the measure of acidity or alkalinity of solution. Hydrogen ion concentration determine how
acidic or basic is the solution. Greater hydrogen ion represents strong acid while small hydrogen
ion concentration represents strong base. pH scale ranges from 0-14.
pH= -log [H+]
Use of measuring pH at PPTA:
pH analyzers are installed at Neutralization tanks, boilers, cooling tower, caustic scrubber etc.
 pH ANALYZER
A pH analyzer have the following three major components:
1. pH sensor
2. Pre Amplifier
3. Transmitter
There are two electrodes in pH sensor; Measuring electrode and Reference electrode.
Measuring electrode is pH sensitive and generates mV after sensing process pH.

Reference electrode maintains a constant voltage when immersed in reference solution. RTD
is immersed in the process to correct the pH at operating temperature.
After generating the mV signal, it is amplified by Pre Amplifier for further processing. After
that the signal is transmitted to the indicator and DCS.
 CONDUCTIVITYANALYZER
One characteristic that all ions have in common is their ability to conduct electric current, that is,
their conductivity. The measurement of the ease with which electrical current flows through the
material is called conductivity. Conductivity depends upon:
1. Concentration
2. Mobility of ions
3. Valence of ions
4. Temperature
Conductivity is measured in unit of mhos/cm, micro Siemens/cm.
There are two types of conductivity sensors:
 CONTACTING CONDUCTIVITY:
Contacting conductivity sensor consists of two metal plates dipped in electrolyte solution. An
AC voltage is applied to the plates and resulting current flow between the plates determine the
conductivity.

 TOROIDAL CONDUCTIVITY:
This types of arrangement consists of two toroid coils, toroid drive coil and toroid sense coil,
dipped in electrolyte solution. As AC current passes through the toroid drive coil, current is
induced in the electrolyte solution. This induced solution current, in turn, induces a current in the
toroid sense coil. The amount of current induced in the toroid sense coil is proportional to the
solution conductivity.
 OXYGEN ANALYZER
Two sealed spheres filled with nitrogen are suspended in a magnetic field. N2 is slightly
diamagnetic, and the resting position of the beam is such that the spheres are displaced
away from the strongest portion of the field. If the surrounding gas contains oxygen, the
spheres are pushed further out of the field by the relatively paramagnetic oxygen. The
magnitude of the torque is related to the paramagnetic characteristics of the gas mixture
and is proportional to the O2. Movement of the dumbbell is detected by photocells, and a

feedback current is applied to the coil encircling the spheres, returning the dumbbell to
the zero position. The restoring current, and hence the output voltage, are proportional to
the O2.
 CARBON DIOXIDE ANALYZER
If the analyzer is to measure carbon dioxide, the chambers must contain a certain amount
of these gases. The infrared light is emitted and passes through the sample gas, a
reference gas with a known mixture of the gases and then through the "detector"
chambers containing the pure forms of the gases. When a "detector" chamber absorbs
some of the infrared radiation, it heats up and expands. This causes a rise in pressure
within the sealed vessel that can be detected either with a pressure transducer or with a
similar device. The combination of output voltages from the detector chambers from the
sample gas can then be compared to the output voltages from the reference chamber.
CONTROL VALVES
The control valves manipulates a flowing fluid, such as gases, steam, water, or chemical
compounds, to keep the regulated process variable as close as possible to the desired set point.
Control Valve is also termed as the Final Control Element.
 CONTROLVAVE PARTS:
1. Actuator
 Diaphragm
 Cylinder
 Piston
2. Yoke
 Stem
 Coupling
 Indicating scale
 Mounting frame
3. Body

 Seat
 Plug
 Cage
TYPES OF CONTROLVALVES
 FAIL TO CLOSE: They are normally closed and need air pressure to open. They are
held open by springs until the pressure is maintained. As the air pressure fails, the spring
bring it back to closed position.
 FAIL TO OPEN: They are normally open and needs air pressure to close. They are held
closed by springs until the pressure is maintained. As the air pressure fails, the spring
bring it back to open position.
On the basis of working principle and application, there are following few different valves,
 GLOBE VALVE
It is a type of valve used for regulating flow in a pipeline, consisting of a movable disk-
type element and a stationary ring seat in a generally spherical body.

 GATE VALVE
It is a valve that opens by lifting a round or rectangular gate out of the path of the fluid.
 BALL VALVE:
A ball valve is a valve with a spherical disc, the part of the valve which controls the flow
through it.
 BUTTERFLYVALVE
A butterfly valve is a valve which can be used for isolating or regulating flow.

 ANGLE VALVE:
An angle seat piston valve is a pneumatically-controlled valve with a piston actuator
providing linear actuation to lift a seal off its seat. The seat is set at an angle to provide
the maximum possible flow when unseated. Angle seat piston valves are particularly
suited to applications where high temperatures and large flow rates are required.
FLOW CHARACTERISTICS
These characteristics determine the relationship between the amount of closure member
movement and the amount of opening of the valve.
 LINEAR: Flow rate increases linearly with rated valve travel.
 EQUAL PERCENTAGE: Flow capacity increases exponentially with valve travel.
Equal increments of valve travel produce equal percentage changes in the existing Cv. Cv
of control valve is the number of U.S. gallons per minute of 60℉ water that will flow
through a valve with a one pound per square inch pressure drop.
 QUICK OPENING: Provide large change in flow rate for very small change in valve
travel.

Valve opening 30% 70% 100%
Quick opening 62 90 100
Linear 30 70 100
Equal percentage 8 33 100
CONTROLVALVE AUXILIARY
 POSITIONER: it controls flow, reduce dead time by boosting the signal to actuator,
determine the split range of the valve, and determine the valve as FTO or FTC.
Input and output signals of positioner:
I. Instrument air supply 7 bar
II. Pneumatic input (3-15 bar) from I/P converter
III. Output of actuator maximum 1-5 bar
 AIR REGULATOR: It is used to regulate the air from 7bar according to the type of
actuator.
 I/P CONVERTER: It receives 4-20mA signal as its input and gives a pneumatic output
to the positioner.
 LOCK-UP RELAY: It operates in the event of pressure supply failure. It is used to lock
in at existing actuator loading pressure. It has an internal a spring/plug arrangement
which traps the air so that the actuator remains at loaded pressure.
 BOOSTER RELAY: It provides bulk air with increased volume and pressure. It is used
where high pressure actuators are required.

 LIMIT SWITCH: It operates discrete inputs to DCS. It operates according to movement
of valve stem.
 FEEDBACK POSITIONER: It gives a 4-20mA feedback signal to DCS through an
extra output.
At LCPL, total of 705 different valves are installed.
DISTRIBUTED CONTROL SYSTEM (DCS)
Distributed control systems (DCSs) are dedicated systems used to control manufacturing
processes that are continuous or batch-oriented, such as oil refining, petrochemicals, central
station power generation, fertilizers, pharmaceuticals, food and beverage manufacturing, cement
production, steelmaking, and papermaking. DCSs are connected to sensors and actuators and use
set point control to control the flow of material through the plant. Here is the DCS system of the
plant at LOTTE.
 FIELD CONTROL STATION (FCS): It consists of input/output modules, CPU and
communication bus.
 OPERATOR STATION (OS): It is basically human interface machine with monitor;
the operator man can view the process in the plant.
 ENGINEERING STATION (ES): It is used to configure all input & output and drawing
and any things required to be monitored on Operator station monitor.

DCS AT LCPL
The DCS used at LCPL is Delta V of Emerson Process Management.
WORKING OF DELTAV
 FROM JUNCTION BOX (JB) TO MARSHALLING CABINET (MC)
4-20mA signals transmitted by the transmitters from the field are sent to the junction box.
From JB, signals travel to MC. In MC, these signals are separated on the basis of
input/output and analog/digital signals into Elko cable.
 FROM MC TO DCS CABINET
From marshalling cabinet Elko comes to the DCS cabinet where signals are connected to
the I/O cards. There are separate cards for digital in, digital out, analog in and analog out.
Elko is terminated in the respective card. In DCS cabinet there are controllers and power
supply as well. These controllers process the input and output according to the user
defined program and the power supply provides power to the controllers and I/O cards.
PROGRAMMABLE LOGIC CONTROLLER (PLC)
A PLC is a digital computer which is used for automation of electromechanical processes. It is a
solid state control system that continuously monitors the status of devices connected as inputs.
Based upon a user written program, stored in memory, it controls the status of devices connected
as outputs. It is designed for multiple inputs and output arrangements, extended temperature
ranges, immunity to electrical noise, and resistance to vibration and impact.
INSTRUMENTS
JUNCTION BOX
(JB)
MARSHALLING
CABINET
(MC)
ELKO CABEL
DISTRIBUTED
CONTROL SYSTEM
(DCS)

COMPONENTS OF PLC
 POWER SUPPLY:
It provides the voltage needed to run the PLC components.
 I/O MODULES:
It connects the PLC to external field devices. The main purpose of the I/O Module is to
condition various signals received from or sent to the external input and output devices.
Input modules converts signal from discrete or analog input devices to logic levels
acceptable to PLC’s processor and output modules converts signal from the processor to
levels capable of driving the connected discrete or analog output devices.
 PROCESSOR:
The processor executes and processes the inputs and outputs according the program. It is
the decision-maker of PLC.
 PROGRAMMING DEVICE:
It is used to transfer the program to the PLC that will determine the sequence of operation
and control of process equipment or driven machine. Usually program transfer is done
through a PC.

PLC OPERATING CYCLE
 INPUT SCAN:
In this step, PLC scans the state of all input devices that are connected.
 PROGRAM SCAN:
Process/execute the user created program logic.
 OUTPUT SCAN:
It energizes or de-energizes the output devices connected to the PLC.
 HOUSEKEEPING:
It includes communications, programming terminals, internal diagnostics, etc.
PROGRAMMINGLANGUAGES OF PLC
 LADDER LOGIC
This is the easiest programming language for PLC. Most basic symbols are shown below:
INPUTSCAN
PROGRAMSCAN
OUTPUTSCAN
HOUSEKEEPING

 FUNCTIONAL BLOCK DIAGRAM (FBD)
Functional block diagram (FBD) provides another view of a set of instructions. Each
function has a name to designate its specific task. Functions are indicated by rectangle.
Inputs are shown on left side while outputs are shown on the right side of the rectangle.

FIRE/GAS & PA SYSTEM
FIRE AND GAS SYSTEM
Fire and gas system is needed for safety and protection of the plant and the workers.
 MAIN FIRE PANEL (FD001/FD002):
This is the main fire detection panel located in the rack room. There are many electronic
cards, each card represents specific zones. This panel indicates normal, fault, and fire
condition. If we have to test whether the detector are working in a specific zone or not,
then we can isolate that zone from this panel. Isolation is necessary because if the system
was not isolated then during testing of the detectors, fire alarms would start and cause
panic in the whole area.
 MIMIC PANEL:
This panel is located in the control room. Fire alarm sounders in the building and on-site
can be initiated and silenced from this panel.

 FIELD EQUIPMENTS:
o Manual Call Point (MAC)
o Smoke Detectors
o Heat Detectors
o Flame Detectors
o Linear heat detector cable
o Fire alarm bells
 SATELLITE FIRE PANELS:
These are the panels located in the buildings. They provide indication of local fire
detection and alarm circuits within the building. These panels will also sent data to the
main fire panel.
 FIRE SPRINKLER SYSTEM:
This system is used where it is required to spray water or foam. Sprinklers are used to
spray water or foam. Sprinklers are connected to piping network and there is water
supply in the pipes. The water is blocked by a heat-sensitive glass bulb so that water does
not fall in normal condition. When there is fire, this glass bulb melts, due to which water
starts to sprays.
 FM200:
This is automatic fire extinguishing and detecting unit. It is mostly used in server rooms,
where there is a risk of electrical fire. As soon as the detector detects fire it generates an
alarm and shows its indication on the fire panel of fm200. After some delay, this panel
will automatically release heptafluoropropane gas to extinguish fire.
CO-GENERATION (CO-GEN)
Co-gen provides electricity and steam to run the process. It starts operation from august 2012,
before that electricity was taken from K-ELECTRIC and steam from the boilers by using natural
gas. Because of co-gen the quality of product is increased. The total power required to run this
plant is about 27MW and the steam required is 50 tons/hr.
After co-gen, electricity is produced by gas turbine generator (GTG) and steam is made using the
exhaust gas of the turbine.

 MAJOR PLANT ITEM (MPI)
GTG at LCPL (Model No. GE LM6000PD) can generate 48.5MW of electricity. It uses
natural gas as fuel compressed at about 48-50bar pressure. Air is used as working mixture
and it is taken from the atmosphere which is compressed at 65bar, and then it is
combusted using natural gas in the combustion chamber due to which the expansion takes
place which drives the turbine and electricity is generated.
 HEAT RECOVERYSTEAM GENERATOR (HRSG)
The GTG generates heat which it expels through it exhaust. The heat energy released
from the turbine is used to heat water due to which super-saturated steam is created that is
used core areas.
 NATURAL GAS BOOSTERCOMPRESSOR (NGBS)
NGBC works with an electric motor of 2.2MW. It is used to compress natural gas from
2bar to 50bar.The are two NGBCs at LCPL which are of type Three Stage Four Throw
Compressor, which means that the pressure of natural gas changes from 2bar to 50 bar in
three stages and four cylinders are used. The natural gas is compressed in three stages
because if the gas is compressed in one stage then lot of heat will be generated which has
a hazard of generating fire. So the gas is compressed in stages, after each stage it is sent
to the intercooler where it is cooled and then sent back again to the compressor for
compression.
At 1st stage: air compressed from 2-10bar.
At 2nd stage: air compressed from 10-25bar.

At 3rd stage: air compressed from 25-50bar.
 CONTOLSYSTEM
At LCPL, DCS and SCADA is used in co-gen control station. System of ABB is used in
LCPL. About 2000 loops work in parallel, of which 1600 loops are of turbine and 400-
500 loops are of HRSG.

ASSIGNMENTS
VON KARMAN
EFFECT:
In fluid dynamics, a Karman
vortex sheet (or a von Karman
vortex sheet) is a repeating
pattern of
swirling vortices caused by
the unsteady separation of
flow of a fluid around blunt
bodies. It is named after the
engineer and fluid
dynamists Theodore von
Karman.
Both the ocean and atmosphere are fluids, in constant motion. On our limited "human"-scale, we
are aware of this motion when we feel the wind blow, or when we encounter a current running
along the beach while swimming. Yet our eyes alone can rarely observe the larger scale of fluid
motion in the ocean and atmosphere.
The phenomenon that is shown in the image of Guadalupe Island at the top of this page (acquired
on August 20, 1999) features a ubiquitous occurrence in the motion of fluids—a vortex street,
which is a linear chain of spiral eddies called von Karman vortices.
Von Karman vortices form nearly everywhere that fluid flow is disturbed by an object. In the
cloud images shown on this page, the "object" that is disturbing the fluid flow is an island or
group of islands. As a prevailing wind
encounters the island, the disturbance in the
flow propagates downstream of the island in
the form of a double row of vortices which
alternate their direction of rotation.

The figure below shows how a von Karman vortex street develops behind a cylinder moving
through a fluid.
"As a fluid particle flows toward the leading edge of a cylinder, the pressure on the particle rises
from the free stream pressure to the stagnation pressure. The high fluid pressure near the leading
edge impels flow about the cylinder as boundary layers develop about both sides. The high
pressure is not sufficient to force the flow about the back of the cylinder at high Reynolds
numbers. Near the widest section of the cylinder, the boundary layers separate from each side of
the cylinder surface and form two shear layers that trail aft in the flow and bound the wake.
Since the innermost portion of the shear layers, which is in contact with the cylinder, moves
much more slowly than the outermost portion of the shear layers, which is in contact with the
free flow, the shear layers roll into the near wake, where they fold on each other and coalesce
into discrete swirling vortices. A regular pattern of vortices, called a vortex street, trails aft in the
wake."
The "Reynolds number" is the ratio of inertial forces to viscous forces in a fluid. The Reynolds
number indicates the likelihood of turbulent (rather than laminar) flow in a fluid. As an example,
two paddles moving at the same speeds—one through a bucket of water and one through a
bucket of paint—will have different Reynolds numbers associated with the fluid flowing around
them. The Reynolds number in the tub of paint will usually be lower.
The picture below shows what happens when the fluid flow rate is increased, and a comb (rather
than a single cylinder) is placed in the film.

DIFFERENCEBETWEEN PLC AND DCS:
PLC is a Programmable Logic Controller. Its main purpose is to replace the relay logic controls
which are "On" or "Off". And DCS "Distributed Control Systems" its emphasis is fast analog
handling because of communications through Bus systems, networking and etc.
PLC is a programmable Logic controller which is used mainly for interlocking different
equipment. PLC is used for particular machine or production unit. PLC is economically low cost.
PLC'S can handle analog and digital I/O as earlier it could handle only digital. PLC'S are
automatic controllers which are a substitute to hard wired controllers. They are extensively used
for automation. PLC is for stand-alone system. PLC is used commonly with OnOff (Digital)
Control and may be expanded with Analog IO Modules for Analog Control and used for a
control task.
Distributed control system does what a PLC would do, but the difference is that a DCS is used in
much larger and complex applications for example power generation, chemical processing etc.
DCS is the System in which controller are distributed geographically and integrated all the control
hardware .which is connectedfrom the various field devices .DCS having its own network, Controller and
HMI etc. Honeywell,Yokogawa,Invensys,ABB,Emersonare the leadingDCSVendors.
TWO WIRE AND FOUR WIRE TRANSMITTERS:

Basically 2 wire transmitters are devices which receive its power supply of DC voltage and in the
same loop generate a 4-20mA signal according its process variable.
4 wire transmitters receive a power supply (24VAC, 120VAC, 220VAC, 24VDC...etc.) in two
wires and in the other two wires generate a 4-20mA signal according the process variable.
To sum up, 2 wires has the current signal in the supply loop and 4 wires has current signal
independently of the supply loop.
LOOP ISOLATORS:
Loop powered isolators are necessary when an extra isolated 4/20mA output is required in areas
where no power is available.
A loop powered isolator’s power is provided by its 4/20mA input current. This makes it possible
for an existing 4/20mA loop to be used to provide another isolated 4/20mA output through a loop
powered isolator.
A loop powered isolator is basically a center tapped transformer which has the input 4/20mA
current flowing through its center tap on the primary. An oscillator circuit alternately switches
the current through each half of the primary. This alternating current creates a current in the
secondary of the transformer. The voltage out of the secondary is rectified and filtered.
The turn ratio on the transformer is designed with a slight step down so the current out of the
secondary is slightly greater than the input current.
This is a simple form of a loop power isolator, but it has shortcomings in that the transformer is
not perfectly linear over the current range. The current is also sensitive to the load resistance on
the secondary.

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