Instrumentation

MIDTERM EXAM CDM

METER

one ten-millionth of the distance  from the equator to the North Pole along a great  circle, so the Earth's circumference is approximately  40000 km.

MEASUREMENTS

 is the acquisition of information about a  state or phenomenon (object of measurement) in the  world around us.  

STANDARDS

Something set up or established by an authority as  a rule for the measure of quantity, weight, extent,  value, or quality.

A definite magnitude of a quantity, defined and  adopted by convention or by law, that is used as a  standard for measurement of the same kind of  quantity.

UNIT OF MEASUREMENT

which was quickly developed in France but did not take  on universal acceptance until 1875 when The Metric  Convention Treaty was signed by 17 nations.

METRIC UNIT

originally defined in 1795 as the  

mass of 1000 cubic cm of water.

KILOGRAM

Is in contact with the process and gives an output  which depends in some way on the variable to be  measured

SENSING ELEMENTS

a device that converts energy forms such as  movement, electrical signals, radiant energy,  thermal or magnetic energy etc, into another form  of energy.

TRANSDUCER

This presents the measured value in a form which  can be easily recognized by the observer

DATA PRESENTATION ELEMENT

A mechanical  device that converts  electrical energy into  other form of energy usually motion.

ACTUATOR

The relationship between the system input and output  when the measured quantity (measurand) is varying  rapidly.

DYNAMIC

is the closeness of a measurement to the true value

ACCURACY

The stability of a system is its ability to give the  same output when used to measure a constant  input over a period of time. 

STABILITY

is the closeness of agreement among a set of  results

PRECISION

is a term that is closely related to  accuracy and defines the maximum error that is to  be expected in some value. 

TOLERANCE

Resolution is the lower limit on the magnitude of  the change in the input measured quantity that  produces an observable change in the instrument  output. 

RESOLUTION

 The input range defines the minimum and maximum  values of a quantity that the instrument is designed to  measure.

SPAN

The stability of a system is its ability to give the  same output when used to measure a constant  input over a period of time. 

STABILITY

is the increment of the output signal (or response) to  the increment of the input measured signal

SENSITIVITY

Reproducibility is the ability of a measurement to  be duplicated, either by the same person or by  someone else under changed conditions.

REPRODUCIBILITY

This is the time taken for the output to rise to  some specified percentage of the steady-state output. 

RISE TIME

This is the time taken for the output to  settle to within some percentage,

SETTLING TIME

 a device that converts energy forms such as  movement, electrical signals, radiant energy,  thermal or magnetic energy etc, into another form  of energy.

TRANSDUCER

an electrical switch operated by an  applied magnetic field

REED SWITCH

The sensor consists of a coil and a circuitry that  senses changes in the magnetic flux, e.g. by a  passing by the sensor.

Operate under the electrical principle of Faraday's  Law of inductance

INDUCTIVE PROXIMITY SENSOR

Long range (20m) 

• Alignment is critical

THROUGH BEAM

Detect the radiation of  warm objects in the far infrared spectral range 

PIR

The working principle of This sensor is  quite the same like of the Infrared Reflection  Sensor.

are self-contained ^{solid-state devices designed for non} contact sensing of solid and liquid  objects.

ULTRASONIC PROXIMITY

Long range (20m) 

THROUGH BEAM

sensor is an electronic  

instrument which is used to sense  

certain characteristics of its  

surroundings by either emitting and/or  detecting

INFRARED

is consist of a resistance track with  connections at both ends and a wiper which moves  along the track as you turn the spindle. 

POTENTIOMETER

Active sensors generate high frequency waves and  evaluate the echo which is received back by the  sensor, measuring the time interval between  sending the signal and receiving the echo to  determine the distance to an object.

TIME OF RETURN

is the  change in frequency or wavelength of a wave for an  observer who is moving relative to the wave  source.

DOPPLER EFFECT

Resemble potentiometers mentioned earlier but  are non-contact optical devices used for converting  the angular position of a rotating shaft into an  analogue or digital data code. In other words,  

• Convert mechanical movement into an electrical  signal (preferably digital).

ENCODER

These two outputs are displaced at 90^o out of  phase from each other with the direction of  rotation of the shaft being determined from the  output sequence.

QUADRATURE ENCODER

Is a displacement or distance measuring  transducer. 

• These are commonly used for position feedback • sensors operates on the principle of a Transformer.

LVDT

It is a device which measures the angular speed of a  rotating shaft.

TACHOMETER

 They provide a unique output code for every single  position of rotation indicating both position and  direction.  

• Their coded disk consists of multiple concentric  "tracks" of light and dark segments.  

ABSOLUTE ENCODER

The angular speed is represented by the  __________of the generated voltage

FREQUENCY