CLASSIFICATION OF INSTRUMENTS, CONTROLS, VARIABLES

Question 1

-An instrument which, if not conforming to specification, could potentially compromise product or process quality and
safet

Answer 1

CRITICAL INSTRUMENT

Question 2

An instrument whose function is not critical to product or process quality, but whose function is more of an operational
significance. An instrument whose function is not critical to product or process quality, but whose function is more of an
operational significance.

Answer 2

NON-CRITICAL INSTRUMENT

Question 3

-An instrument whose function is not critical to product quality, not significant to equipment operation, and not used for
making quality decisions.

Answer 3

REFERENCE ONLY

Question 4

-in process industries it refers to the regulation, command or direction of all aspects of the process

Answer 4

CONTROL

Question 5

2 TYPES OF CONTROL

Answer 5

MANUAL CONTROL
AUTOMATIC CONTROL

Question 6

-refers to the methods of changing or refining raw materials to create end products

Answer 6

PROCESS

Question 7

-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

Answer 7

PROCESS CONTROL

Question 8

-an arrangement, set or collection of physical components connected or related in such a manner as to form and/or act as
an entire uniT

Answer 8

SYSTEM

Question 9

-an arrangement of physical components connected or related in such a manner as to command, direct or regulate itself
or another system.

Answer 9

CONTROL SYSTEM

Question 10

-an arrangement of two or more instruments connected together to
perform a unified task

Answer 10

INSTRUMENTATION SYSTEM

Question 11

-a process management system designed to maintain a process variable at a desired set point.

Answer 11

CONTROL LOOP

Question 12

2 TYPES OF CONTROL LOOP

Answer 12

CLOSED AND OPEN CONTROL LOOP

Question 13

–exists when a process variable is measured, compared to a setpoint and action is taken to correct any deviation from
setpoint.

Answer 13

CLOSED LOOP

Question 14

-exist when the process variable is not compared, and action is taken not in response to on the condition of the process
variable

Answer 14

OPEN LOOP

Question 15

-a value for a process variable that is desired to be maintained

Answer 15

SETPOINT

Question 16

ELEMENTS OF THE INSTRUMENT LOOP

Answer 16

1. Process
2. Measuring Element
3. Receiving Element
4. Final Control Elemen

Question 17

-Any operations or sequence of operations involving a change of energy, state, composition, dimension or other properties
that may be defined with respect to a datum/data.

Answer 17

Process

Question 18

• any variable property of a process

Answer 18

PROCESS VARIABLE

Question 19

• any input variable that seats the desired value of the measured variable.

Answer 19

SET POINT

Question 20

– outputs signal generated in response to a change of a process variable.

Answer 20

CONTROLLER OUTPUT

Question 21

-a process variable linked to the controller output that is used to influence the measured variable.

Answer 21

Manipulated variable

Question 22

MAJOR PROCESS VARIABLES

Answer 22

• PRESSURE
• LEVEL
• FLOW
• TEMPERATURE

Question 23

MINOR PROCESS VARIABLES

Answer 23

ANALYSIS
POSITION
SPEED
+MORE

Question 24

A combination of two or more instruments or control functions arranged so that signal pass from one to another for the
purpose of measurement and/or control of a process variables

Answer 24

Instrumentation & Control Loop or Instrument Loop

Question 25

-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

Answer 25

PROCESS CONTROL

Question 26

The determination of the magnitude of a variable (VALUE

Answer 26

MEASUREMENT

Question 27

The determination of the existence or the presence of a variable

Answer 27

DETECTION

Question 28

The limit or extent of variation.

Answer 28

RANGE

Question 29

The lower limit is called _______

Answer 29

LRV

Question 30

the upper limit is called _______

Answer 30

URV

Question 31

The number of units between two limits

Answer 31

SPAN

Question 32

a signal that has no discrete positions or states and changes value.

Answer 32

ANALOG SIGNAL

Question 33

a signal that generates or uses binary digit signals to represent continuous values or discrete
states.

Answer 33

DIGITAL SIGNAL

Question 34

TYPES OF MEASURING OUTPUTS

Answer 34

1. Sensor
2. Transmitter
3. Transducer
4. Process Switch

Question 35

The part of Instrument loop or instrument that first senses the value of a process variable, and that assumes a
corresponding, predetermined, and intelligible state or output.
- 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.

Answer 35

SENSOR

Question 36

A device that senses a process variable through the medium of a sensor and has an output whose steady-state
value varies only as a predetermined function of the process variable.

Answer 36

TRANSMITTER

Question 37

A general form of a device that receives information in the form of one or more physical quantities, modifies the
information and/or its form, if required, and produces a resultant output signal.

Answer 37

TRANSCUDER

Question 38

-a device that converts one type of signal into another type of signal.

Answer 38

CONVERTER

Question 39

-a device that converts a reading from one sensor or transducer into a standard and transmits that signal to a monitor or
controller

Answer 39

TRANSMITTER