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WorksheetsInstrumentation and control engineering
Total questions: 120
Worksheet time: 2hrs 45mins
branch of physics which deals with the measuring,
monitoring and controlling variables in a process
industry.
(a)
In general definition, this can be defined as the art of and science of measurement and/or control
(a)
Any device used directly or indirectly in order to accomplish an objective or task
(a)
Is any sensing, measuring, transmitting, indicating, or controlling device associated with a process (including process variables) or system
(a)
a device capable of detecting change, physical or otherwise, in a particular process. It then converts these physical changes into some form of information understandable by the user
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Simplest form of measurement. It allows us to know the current state of the variable
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CLASSIFICATION OF INSTRUMENTS
an instrument which if not conforming to specification, could potentially comprise product or process quality and safety
Critical
Non-critical
Reference only
An instrument whose function is not critical to product or process quality, but whose function is more of an operational significance
(a)
An instrument whose function is not critical to product quality, not significant to equipment operation, and not used for making quality decision
(a)
In process industry, it refers to the regulation, command, or direction of an aspects of the process
(a)
2 types of control
(a)
Refers to the methods of changing or refining raw materials to create end product
(a)
The regulation or manipulation of variables influencing the conduct of a process in such a way as to obtain a product of desired quality and quantity in an efficient manner
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An arrangement, set or collection of physical components connected or related in such a manner as to form or act as an entire unit
(a)
an arrangement of physical components connected or related in such a manner as to command, direct or regulate itself or another system
(a)
an arrangement of two or more instruments connected togetehr to perform a unified task
(a)
a process management system designed to maintain a process variable at a desired set point
(a)
exists when a process variable is measured, compared to a setpoint and action is taken to correct any deviation from setpoint
closed control loop
open control loop
setpoint
exist when the process variable is not compared, and action is taken not in response to on the condition of the process variable
closed control loop
open control loop
setpoint
a value for a process variable that is desired to be maintained
(a)
Measures process parameters and variables. Measurement of the variables or properties are based on certain unique phenomena, such perties are based on certain unique phenomena, such as physical, chemical, thermo-electrical factors
primary elements/sensor
secondary element/signal-generating element
controlling element/controller
final control element
(a) sensed by the primary element cannot be transmitted unless converted to an electrical (or pneumatic) signal by a secondary element
Integral part of loop that first senses the value of a process variable that assumes a corresponding predetermined state and generates an output signal indictive of or proportional to the process variable
(a)
a device that is used to detect the presence of something, such as flammable or toxic gases or discrete parts
(a)
a device that translates a mechanical signal into an electrical signal
(a)
a device that converts one type of signal into another type of signal. (current into voltage, analog to digital)
(a)
a device that converts a reading from one sensor or transducer into a standard and transmits that signal to a monitor or controller
(a)
Types of Signal
a signal that has no discrete positions or states and changes value
(a)
a signal that generates or uses binary digit signals to represent continuous values or discrete states
(a)
Known as the controller and is the brain of the control system and performs appropriate functions for maintaining the desired level (set point) of parameters to restore quality and rate of production
(a)
a device that receives data from a measurement instrument , compares that data to a programmed setpoint, and, if necessary, signals a control element to take corrective action
(a)
usually computers connected to a set of input/output (I/O) devices. The computers are programmed to respond to inputs by sending outputs to maintain all processes at setpoint
(a)
are controllers that, in addition to performing control functions , provide readings of the status of the process, maintain databases amd advance man-machine interface
(a)
The part of the control system that acts to physically change the manipulated variable. Typically used to increase or decrease fluid flow
(a)
the part of a final control device that causes a physical change in the final control device when signalled to do so
(a)
manipulate the flow rate of gas or liquid; whereas, the control switches manipulate the electrical energy entering a system
(a)
How is intrumentation implemented?
(a)
It is the overall design document for a process plant
(a)
P&IDs (original)
(a)
P&IDs (also used)
(a)
PFD (simplified version of the P&ID)
(a)
are the "schematics" used in the field of instrumentation and control (Automation)
(a)
Types of Instrumentation Symbols
(a)
______ denote function while the ______ in the middle denote location or mounting
(a)
(a) indicate how instruments are connected to each other and to the process and represents the types of signals transmitted in the process. It could either be a process line symbol or a signal line symbol
Process piping is generally shown in (a)
(a) indicate instrument-to-process connections or instrument tubing
(a) indicate the type of signal that connects two instruments
Indicates the action of actuation in a valve-actuator instrument and also indicates the position during fail mode
(a)
(a) are usually drawn as a bow tie shaped symbol
(a) an alphanumeric code that provides specific information about an instrument or its function
Tag Numbers contain two information:
(a)
(a) numbers indicate the loop/system in which an instrument belongs
(a) series of f letters, or letter code, that identifies the function of the instrument
In a functional identifier, first letter identifies the (a)
Succeeding letters desigante one or more (a)
It is the fundamental representation of a process that schematically depicts the conversion of raw materials to finished products without delving into details of how that conversion occurs. It defines the flow of material and utilities, basic relationships between major pieces of equipment, and establishes the flow, pressure and temperature ratings of the process
(a)
Is an alphanumeric list of date related to a facility’s instrumentation and control systems components and functions.
(a)
Drawings used to design and define the on-off or sequential part of a continuous process plant. May involve the action of a simple switch or it may entail a series of steps comprising a complex automatic system
(a)
A schematic representation of a single control loop including its hydraulic, electric, magnetic and pneumatic components
(a)
Used to show how the instrumentation and control system components are connected and interconnected to the process. Define the requirements to co
(a)
Orthographic views of the plant, drawn to scale, that show the locations of instruments and control system components. Show other control system hardware including marshalling panels, termination racks, local control panels, junctions boxes, instrument racks, and power panels
(a)
(a) is an important subsystem of a mechatronics system. Its main function is to collect the information on system status and to feed it to the micro-processor(s) for controlling the whole system.
Measurement system comprises of ______, _______, and ___________
(a)
The process variable is directly measured in units that represent the basic nature of that variable.
(a)
(a) is the measurement of a process variable indirectly by using another variable
Type of measurement - the measurement depends on a fixed value of the process variable. The reading is indicated either as high or lo
(a)
Type of measurement - the measurement indicates the actual value of the process variable
(a)
(a) refers to the capability of the instrument to measure a variable
- refers to the set of values within the instrument measuring range where the scaled output; 4-20 mA, 3-15 psi or 1-5 V is set during calibration
(a)
It is the distance (or difference) between the upper range value (URV) and Lower range value
(a)
(a) is the highest value of the measured process variable that the output of a transmitter is currently configured to measure
(a) is the lowest value of the measured process variable that the analog output of a transmitter is currentl
The lamp will energize only if someone presses the switch, holding its normally-open contacts in the closed position. Normally-open switch are sometimes referred to in the electrical industry as form-A contacts
(a)
The lamp would energize only if the switch was left alone, but it would turn off if anyone pressed the switch. Normally-close switch are sometimes referred to in the electrical industry as form-B contacts
(a)
A (a) is an electrical switch actuated by a person’s hand motion. This may take a form of toggle, pushbutton or rotary
A (a) detects the physical motion of an object by direct contact with that object. It will be in its “normal” status when it is not in contact with anythin
A (a) detects the proximity (closeness) of an object. By definition, these switches are non-contact sensors, using magnetic, electric or optical means to sense the proximity o
A (a) detects the presence of fluid pressure. This often use diaphragms or bellows as the pressure sensing elements, the motion of which actuates o
A (a) detects the level of liquid or solid (granules or powder) in a vessel. This often use floats as the level-sensing element, the motion of which actuates one or more switch contacts
A (a) detects the temperature of an object. It often use bimetallic strips as the temperature-sensing element
A (a) detects the flow of some fluid through pipe. It often use “paddles” as the flow-sensing element, the motion of which actuates one or more switch conta
It is the fluid equivalent of an electrical switch: a device that either allows unimpeded flow or acts to prevent flow altogether
(a)
An (a) is a voltage or current whose magnitude represents some physical measurement or control quantity
Most popular form of signal transmission used in modern industrial instrumentation system
(a)
(a) is a measure of how hot or cold something
is: specifically, a measure of the average kinetic energy of the
particles in a system
While there is no maximum
theoretically reachable temperature, there is a minimum
temperature, known as (a)
Invented the liquid-in-glass thermometer
Galileo Galilei
Athanasius Kircher
Daniel Gabriel Farenheit
Anders Celsius
Invented the first mercury
thermometer
Galileo Galilei
Athanasius Kircher
William Thomson
Daniel Gabriel Fahrenheit
He invented both the mercury and
the alcohol thermometer with Fahrenheit scale
Galileo Galilei
William Thomson
Daniel Gabriel Fahrenheit
Athanasius Kircher
He proposed a centigrade scale
Athanasius Kircher
Anders Celsius
William Thomson
Daniel Gabriel Fahrenheit
He discovered the principle behind the
thermocouple the existence of the thermoelectric current.
C.H. Meyers
Sir Humphry Davy
Daniel Gabriel Fahrenheit
Thomas Seebeck
He noted the temperature dependence of
metals.
Thomas Seebeck
C.H. Meyers
Sir Humphry Davy
Galileo Galilei
Time of the development of temperature sensord fully developed
(a)
The name centigrade was changed to Celcius
(a)
also known as thermometry,
describes the process of measuring a current local
temperature for immediate or later evaluation.
(a)
The (a) is the basis
of most present-day temperature measurements. The scale
was established by an international commission in 1948 with
a text revision in 1960. A revision of the scale was formally
adopted in 1990 and still being used today.
A non-electronic temperature sensor that exploit the principle of fluid expansion
to measure temperature. If a fluid is enclosed in a sealed system
and then heated, the molecules in that fluid will exert a greater
pressure on the walls of the enclosing vessel.
Bimetallic Thermometers
Filled-bulb system
Liquid-in-glass thermometers
_______ use a liquid fill fluid. Here, the volumetric expansion of the liquid
drives an indicating mechanism to show
temperature. The steel bulb, stem
and indicator are completely filled under
pressure with a liquid. The system is totally
filled to provide a constant volume.
Class I
Class II
Class III
Class IV
_______ uses a
volatile liquid/vapor combination to
generate a temperature dependent
fluid expansion. This form of
measurement is based on the vapor-
pressure curves of the fluid and
measurement occurs at the transition
between the liquid and vapor phases.
Class I
Class II
Class III
Class IV
Here, the change in pressure
with the temperature allows us to
sense the bulb’s temperature. As the
volume is kept constant, the pressure
varies in direct proportion to the
absolute temperature. This system do provide a
faster response than other filled
devices, and as it converts
temperature directly into pressure it
is particularly useful in pneumatic
systems.
Class I
Class II
Class III
Class IV
For a Class I type of Filled-bulb sytem, the filling fluid is usually an iner hydrocarbon, such as _______
mercury
xylene
nitrogen
__________ are
different from other liquid filled
systems because of the properties of the
metal. Mercury is toxic and can affect
some industrial processes and is used
less in filled system. Mercury filled
system provides the widest range of
operation (-40 °C to 650°C)
Class I
Class II
Class III
Class IV
These low cost nonelectric sensors are made from heat-
sensitive fusible crystalline solids that change decisively from
a solid to a liquid with a different color at a fixed temperature
depending on the blend of ingredients. They are available as
crayons, lacquers, pellets, or labels
Liquid-in-glass thermometers
Bimetallic thermometers
Filled-bulb systems
Bistate/Phase change sensors
The major uses of this non-electronic thermometer is a quick check of the temperature of an
object is desired, or, in the case of the temperature labels or
stickers, a record of whether the object has exceeded a certain
temperature.
Liquid-in-glass thermometer
Bimetallic thermometer
Filled-bulb system
Bistate/Phase change sensors
A (a) is an assembly of two wires of unlike metals
joined at one end designated the hot end. At the other end, referred to
as the cold junction, the open circuit voltage is measured.
Called the
(a) , this voltage (electromotive force) depends on the
difference in temperature between the hot and the cold junction and
the Seebeck coefficient of the two metals.
If the junctions of a thermocouple are at
the same temperature and a current is passed through the
circuit of the thermocouple, HEAT is produced at one
junction and ABSORBED at the other.
Peltier Effect
Thompson Effect
Seebeck Effect
When two dissimilar metals with
different temperatures and they’re touching, they produce an
emf or voltage
Peltier Effect
Thompson Effect
Seebeck Effect
This law is interpreted to mean that the addition of different
metals to a circuit will not affect the voltage the circuit creates. The
added junctions are to be at the same temperature as the
junctions in the circuit.
Law of Intermediate Metals
Law of Homogenous Materials
Law of Intermediate Temperature
This law states that a thermocouple circuit that is made
with a homogeneous wire cannot generate an emf, even if it is
at different temperatures and thicknesses throughout.
Law of Intermediate Metals
Law of Homogenous Materials
Law of Intermediate Temperature
This law allows a thermocouple that is calibrated with a
reference temperature to be used with another reference
temperature. It also allows extra wires with the same
thermoelectric characteristics to be added to the circuit
without affecting its total emf.
Law of Intermediate Metals
Law of Homogenous Materials
Law of Intermediate Temperature
A
temperature sensor which measures temperature using the
principle that the resistance of a metal changes with
temperature.
Resistance Temperature Detector (RTD)
Thermistors
Pyrometers
Like the RTD, the ______ is also a resistive device
that changes its resistance predictably with temperature. Its
benefit is a very large change in resistance per degree change
in temperature, allowing very sensitive measurements over
narrow spans. Due to its very large resistance, lead wire errors
are not significant.
Resistance Temperature Detector (RTD)
Thermistors
Pyrometer
Thermistors are made of metal oxide
RTD are made of pure metal
True
False
Thermistors are relatively insensitive
RTD are highly sensitive
True
False
Thermistors are non-linear
RTD are very linear
True
False
(a) also called as Radiation Thermometers was
invented by Josiah Wedgwood. They are non-contact
temperature sensors that measure temperature from the
amount of thermal electromagnetic radiation received from a
spot on the object of measurement.
also referred as infrared (IR)
thermometer is a noncontact radiant energy detector. Every
object in the world radiates IR energy. The amount of radiant
energy emitted is proportional to the temperature of an
object. Noncontact thermometers measure the intensity of the
radiant energy and produce a signal proportional to the
target temperature.
Radiation pyrometer
Optical pyrometer
work on the basic principle of using
human eye to match the brightness of the hot object to the
brightness of the calibrated lamp filament inside the instrument.
In this type of pyrometer, a brightness comparison is made to
measure the temperature.
Radiation pyrometer
Optical pyrometer
