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4th 1st Final part II

Terms in this set (35)

The output signal of a discrete sensor can only be on or off.
true
Discrete mechanical sensors have contacts that open and close. Since discrete electronic sensors often do not have mechanical contacts, the output condition is described as activated or de-activated.
true
Capacitive, inductive and ultrasonic are three types of ? sensors that are based on the sensor's operating principles.
proximity
Since solid-state sensors use semiconductor circuits instead of contacts to switch the attached load, the load must match the voltage and current specifications for the sensor.
true
Sensors that use an NPN transistor to switch DC loads are current- ? devices.
sinking
Current-sinking outputs use the ? side of the DC output circuit as the switch leg to the load device.
negative
Sensors that use a PNP transistor to switch DC loads are current- ? devices.
sourcing
Current-sourcing outputs use the ? side of the DC output circuit as the switch leg to the load device.
positive
NEMA sensor symbols
? devices are non-contact solid-state devices that use light to detect the presence of objects.
photoelectric
Electronic sensors with a(n) ? output interface can switch AC or DC without the specific polarity requirements for DC circuits.
relay
A photocell is a photoelectric device that only reacts to ? light.
ambient
The component present in a photoelectric device that provides a light source is a ?
transmitter
The component present in a photoelectric device that detects the presence of the light source is a ?
reciever
Response time, sensitivity, operation margin, and light/dark operation are four parameters that are commonly used to describe the operation of ? devices.
photoelectric
? is measured by the number of light pulses per second that a photoelectric device transmits.
response time
? is the threshold value for received light to trigger a change in the output status of a photoelectric device
sensetivity
The ratio of the available level of light at a photoelectric sensor's receiver to the minimum level of light required to trigger the sensor is the ? .
operating margin
A ? operating margin indicates that a sensor will be reliable when ambient light conditions are variable.
higher
The ? modes enable a photoelectric sensor to detect whether a target is present or absent.
light/dark operation
What is the photoelectric scanning method in which the transmitter and receiver are placed opposite each other?
direct
What is the photoelectric scanning in which the transmitter and receiver are housed in the same enclosure and the transmitted beam is reflected back to the receiver from a reflector?
retroflective
What is the photoelectric scanning method in which the receiver responds only to the depolarized reflected light from a special reflector or polarized sensitive reflective tape?
polarized
What is the photoelectric scanning method in which the transmitter and receiver are housed in the same enclosure and in which a specialized scanning technique is used not only to determine when an object is moved into position but also to identify the specific location of the object?
Diffuse
Proximity sensors that detect objects using an electrostatic field are known as ? devices.
capacitive
Proximity sensors that detect objects using an electromagnetic field are known as ? devices.
inductive
? proximity sensors can only detect metals that conduct current.
inductive
The size of the object and the type of metal (ferrous or nonferrous) are two factors that determine the effective sensing range of a(n) ? proximity sensor.
inductive
A(n) ? proximity sensor can detect a wide range of materials, including metals (ferrous and nonferrous), glass, plastics, and liquids.
capacitive
The size and dielectric properties of the object are the two factors that determine the effective sensing range of a ? proximity sensor.
capacitive
What type of proximity sensor emits a high frequency sound signal and detects the reflected sound from the object?
ultrasonic
? devices are solid-state sensors that detect the presence of a magnetic field.
hall-effect
A primary step in troubleshooting any of the sensors covered is to determine if the sensor has the correct operating input voltage.
true
The sensor in an IEC Standard NPN device must be connected to provide a ? connection to the load.
sinking
The IEC Standard PNP device must be connected to provide a ? connection to the load.
sourcing
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