Inelect Finals
sensing face
- is responsible for the emission of the electrostatic/electromagnetic field in which the target will be exposed. It is also the part that is being exposed to the sensor's target
blind zone
A ___________ exists directly in front of the sensor.
thermistor
A ___________ is a type of resistor whose resistance varies significantly with temperature, more so than in standard resistors.
piezoelectric ceramic disk
A _____________ is mounted in the ultrasonic proximity sensor surface. It can transmit and receive high-frequency pulses. A high frequency voltage is applied to the disk, causing it to vibrate at the same frequency.
thermocouple
A ______________ is a temperature-measuring device consisting of two dissimilar conductors that contact each other at one or more spots, where a temperature differential is experienced by the different conductors
transducer
A device for translating the magnitude of one quantity into another quantity
sensor
A device which provides a usable output in response to a specified measurement
hysteresis
A transducer should produce the same output whether the value has been reached due to a continually increasing input or a continually decreasing input.
electric actuator
An ___________ is powered by a motor that converts electrical energy to mechanical torque.
actuator
An ___________ is usually activated by a low-level command signal, so an amplifier may be required to provide sufficient power to drive the actuator
actuator
An_____________ is also a transducer because it changes one type of physical quantity into some alternative form
phototransistor
As light intensity increases, the basecollector junction resistance of the _________________ decreases. This decrease in resistance increases the base current that in turn increases the flow of collector current
solar cell
As the light (protons) intensity increases, an imbalance of electrons and holes are created, which gives an increase to the open circuit potential voltage difference and therefore a current flow within a circuit.
Thermal or Magnetic actuators
Can be actuated by applying thermal or magnetic energy have been used in commercial applications
Accuracy
Can be expressed as a comparison of the static error of the transducer compared to the actual value expressed as a percentage of full scale.
45 degrees
Coarse-grained materials, such as sand, can have an angular deviation as much as ___________
hyraulic actuators
Consist of a cylinder or fluid motor that uses hydraulic power to facilitate mechanical operation
Pneumatic actuators
Convert energy formed by vacuum or compressed air at high pressure into either linear or rotary motion
6 to 80 cm
Depending on the sensor the blind zone is from ________________
capacitive proximity sensor
Depends upon the dielectric constant of the target. The larger the dielectric number of a material, the easier it is to detect.
Pneumatic actuators
Enable large forces to be produced from relatively small pressure changes
demodulator
Extracts signal amplitude from the oscillating carrier. The extracted amplitude carries the information that is equivalent or linear to the distance of the target object from the sensing face
E.H. Hall
Hall Effect transducer is amed after _____________ and discovered on 1879.
actuators
Hardware devices that convert a controller command signal into a change in a physical parameter
transducers
Helps in reducing the sensitivity of a system to parameter change.
Mechanical actuators
Involve gears, rails, pulleys, chains and other devices to operate. An example is a rack and pinion
photoransistor
Is a three-layer semiconductor device with a light-sensitive collector-base p-n junction.
capacitive proximity sensor
Is similar to inducting proximity sensors.. The main difference between the two types is that ____________________ produces an electrostatic field instead of an electromagnetic field.
Sensitivity
Is the ability of the transducer to generate an output for a given change in input.
Thermocouple
It produces a voltage when the temperature of one of the spots differs from the reference temperature at other parts of the circuit.
Acoustic Transducers
Its applications are acoustic speakers, acoustic microphone, piezoceramic transducers and magnetostrictive tranducers
piezo devices
Its applications are pressure switches, pressure gauges, sonar transducers vibration detectors and ignition devices
light dependent resistors
Its resistance is dependent on the light intensity that falls on the device.
3 degrees
Liquids, such as water, are also limited to an angular alignment of __________
blanking out the background
Objects beyond the upper limit do not produce a change at the output of the sensor. This is known as ____________
proximity sensor
Often emits an electromagnetic or electrostatic field or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal
Linearity
Refers to the change in output compared to the change in input. If the change in output is proportional to the change in input, the transducer is said to be linear.
Inductive proximity sensor
Rely on the effect of a magnet approaching a high turns ratio coil that produces a voltage proportional to the relative distance of that magnetic source from that coil
Thermal or Magnetic actuators
Tend to be compact, lightweight, economical and with high power density
operating range
The ___________ can be adjusted in terms of its width and position within the sensing range. The upper limit can be adjusted on all sensors. The lower limit can be adjusted only with certain versions
flip-flop
The ____________ triggers the output when it has received the feedback signal from the comparator in the demodulator circuit
sensitivity
The _____________ of capacitive sensor is affected by the moisture content and the density of the substance to be sensed
reflex mode
The ______________ uses a reflector located in the preset operating range. The operating range is adjusted for the reflector. The pulses are bounced off the reflector and the echo pulses are returned to the sensor. W
Precision
The ability of the transducer to produce the same output each time the same input is applied.
Angular Alignment
The angle of the target entering the sound cone must also be considered. The maximum deviation from the send direction to a flat surface is ±3°
5 degrees
The approximate angle of the main cone is________
span
The difference between the upper and lower values the transducer is designed to measure.
Range
The highest and lowest values that the transducer is designed to measure.
plus minus 3 degrees
The maximum deviation from the send direction to a flat surface is _________
nominal range
The maximum distance that proximity sensor can detect is defined "_____________"
proximity sensor's target
The object being sensed by the proximity sensor is often referred to as the______________
main cone
The radiation pattern of an ultrasonic sensor consists of a ________ and several neighboring cones.
color
The semi conductive materials used in the manufacture of LED's determines the _________ of the emitted light
Seebeck Effect
The voltage produced at the junction of the dissimilar metals is due to a phenomenon called the ____________
transducer
The word "____________" is the collective term used for both Sensors and Actuators
float transducers
These devices use a sender that is either a switch or some form of resistive device.
diffuse mode
This is the standard mode of operation. Objects, travelling in any direction into the operating range of the sound cone, will cause the sensor output to switch states.
passive sensors
Transducers that produce an output signal in the form of some variation in resistance, capacitance or any other electrical parameter, which than has to be converted to an equivalent current or voltage signal
passive sensors
Transducers which require an external power source for their operation.
parallel sensors
Two sonar sensors with the same sensing range have been mounted parallel to each other. The targets are vertical to the sound cone. The distance between the sensors is determined by the sensing range.
opposing sensors
Two sonar sensors with the same sensing range have been positioned opposite of each other
Pneumatic actuators
Use compressed air as the driving force
hydraulic actuators
Use hydraulic fluid to amplify the controller command signal
piezo devices
Use materials such as quartz and manmade products such as Barium Titanate and Lead Zirconate that demonstrate a characteristic in that when pressure is applied over one axis.
float transducers
Used in tank level monitoring applications
optical devices
Using direct or reflected light can provide an ideal noncontact sensing mechanism.
optical devices
Utilize light and light-intensity as a way of detecting other physical properties.
Inductive proximity sensor
Widely used in modern high speed process control environment for the detection, positioning and counting of ferrous and non-ferrous metal objects.
Thermocouples
___________ are a widely used type of temperature sensor for measurement and control and can also convert a temperature gradient into electricity
Free zones
___________ must be maintained around the sensor to allow for neighboring cones.
Thermistors
______________ are widely used as inrush current limiter, temperature sensors (NTC type typically), self-resetting overcurrent protectors, and selfregulating heating elements.
Thru-beam
______________ sensors consist of a transmitter, which emits ultrasonic pulses, and a receiver. If the beam between the transmitter and the receiver is interrupted the output of the receiver switches state
Mutual interference
___________occurs when sonar devices are mounted in close proximity to each other and the target is in a position to reflect echoes back to a sensor in the proximity of the transmitting sensor.
Hall Effect transducer
a condition if current flow in a conductor being affected by the presence of a magnetic field If an electric current flows through a conductor in a magnetic field
Resistive Strain Gauge
a device that converts a change in applied force into a change in produced resistance.
sensor
acquires a physical parameter and converts it into a signal suitable for processing (e.g. optical, electrical, mechanical)
transducer
an element or device which receives information in the form of one quantity and converts it to information in the same or another quantity or form.
transducer
any device or component that converts an input signal of one form to an output signal of another form
proximity sensors
are used in various facets of manufacturing for detecting the approach of different objects
actuators
can be used to switch voltages or currents
sensors
can be used to sense a wide range of different energy forms such as movement, electrical signals, radiant energy, thermal or magnetic energy etc
Resistive Strain Gauge
consists of a length of resistive wire that is bonded to the surface of an object that receives an applied force
optocoupler
consists of a photo emissive device, LED, and a photoconductive device, phototransistor, contained in a single package
oscillator
creates the repetitive signal with a defined frequency, in which it's amplitude varies depending on the distance of the target from the sensing face
transducer
defined as the device which convert the one form of energy into another form of the energy
proximity sensors
detect an object when the object approaches within the detection boundary of the sensor
Acoustic Transducers
devices that convert a variation in electrical energy into a change in mechanical energy
Photoelectric Transducers
devices that produce an electrical variation in response to a change in light intensity, or produce a light intensity variation due to a change in applied electrical energy.
Mechanical actuators
function by converting rotary motion into linear motion to execute movement
beamwidth
in radio antenna pattern, the angle between the half-power (-3db) points of the main lobe, when reference to the peak effective radiated power of the main lobe.
Light emitting diode
is a semi conductive P-N junction enclosed in a coloured case to enhance the colour of the light output
light dependent resistors
non-linear device with resistance ranging from about 10 MΩ in complete darkness to 100Ω in full sunlight
Photoconductive
one type of photoelectric transducers, and also a semiconductor cell which produces a change in its resistance in response to a change in light intensity.
proximity sensors
provide long range detection, which is evidently more precise than human vision
proximity sensors
sensors able to detect the presence of nearby objects without any physical contact
active sensor
simply detect and respond to some type of input from the physical environment
output
the __________ acts as a switch that is physically connected to the circuitry in which the sensor is wired.
Ultrasonic proximity sensors
use a transducer to send and receive high frequency sound signals. When a target enters the beam the sound is reflected back to the switch, causing it to energize or deenergize the output circuit
transducer
used for compensation in different plants and systems.
Piezo electric buzzers and speakers
used in a wide variety of applications from simple low fidelity applications such as a warning buzzer to high fidelity, high frequency audio speaker applications
