AutomationDirect has been carrying sensors for over twenty years and we now offer over
six hundred inductive proximity sensors.
In this video, we will cover how inductive proximity sensors work and how
to select one for your application.
AutomationDirect offers AC, DC, and analog output sensors with industrial, wash down
and harsh environment ratings and they come in round,
square and rectangular bodies with sizes ranging from
3mm up to 30mm in round sensors.
Let's start with the basics: What is an inductive proximity sensor and what will it detect?
Where would one be used?
Maybe your application needs to detect how fast a piece of machinery is operating and
reading the teeth on a gear will allow a PLC or some other
device to detect the gear rotation speed, maybe do a
math conversion and send the speed to an HMI or display screen.
An inductive proximity sensor is a sensor that produces an electromagnetic field that
detects ONLY metal targets within its sensing zone.
Here are a few examples of the metals an inductive proximity
sensor will detect: iron, brass, aluminum, copper and stainless steel.
Iron is the most common target; other metals will have a de-rating meaning
the target must be closer to the sensor in order to detect.
The material correction factors are published for the sensors AutomationDirect sells here.
The sensing zone of a proximity sensor is determined by the size of the sensor.
Generally, the larger the proximity sensor, the greater the sensing
distance.
An example is this 8mm standard prox sensor.
It has a sensing distance of 1.5mm while this 30mm
standard prox sensor has a sensing distance of 10mm.
AutomationDirect carries many types of inductive proximity sensors.
Two of these types are shielded and unshielded.
A shielded sensor can be flush mounted whereas an unshielded will require a specific
free zone around the sensing face in order not to influence the sensing characteristics.
Why would you want to use an unshielded sensor?
Unshielded sensors have a greater sensing range.
If you look at this sensor, the internal components are extended
past the metal body.
Let's use the same 8mm standard prox we used previously with a sensing distance
of 1.5 mm.
Compare the standard sensor with an unshielded 8mm sensor in the same family;
it has a greater sensing distance of 2.5mm.
We also offer extended, triple and quadruple sensing ranges
in shielded and unshielded body styles.
For example, this quadruple sensing range sensor has a 4mm
sensing distance and is a shielded sensor and this quadruple
sensing range sensor has a 6 mm sensing distance and is an unshielded sensor.
We also offer one-piece stainless steel sensors that offer an IP68 protection rating.
These are fully submersible to 290 psi or 669 feet of water.
Analog proximity sensors still detect metal targets, but they offer a voltage and amperage
output range vs a simple on and off output.
Harsh duty sensors are designed to operate in harsh environments like welding environments
where there are high electromagnetic fields.
We offer sensors for food and beverage packaging where the
sensors are made of FDA approved materials and offer an IP69K rating.
These sensors offer higher ratings so they can be used in high pressure
cleaning applications, corrosive environments, or welding
environments where slag and electromagnetic fields are a concern.
Factor 1 or K1 sensors do not have a derating for dissimilar metals.
For example, a standard sensor 12mm senses steel at 2mm, copper at .44mm,
aluminum at .62mm, brass at .82mm and stainless steel
at 1.54mm.
A K1 or Factor 1 senses all these same materials at the same nominal distance.
K1 sensors are also immune to weld field or electromagnetic
fields present in welding applications.
A big misconception with proximity sensors is that they will not operate if a foreign
substance gets on the sensing tip or comes between the sensing
tip and the target.
If the substance isn't metal, the sensor is designed to continue to detect.
An example would be a sensor on a conveyor that moves cardboard
boxes.
The sensor could get cardboard dust on the face of the sensor.
If the senor is reading a metal target, the dust should not affect the sensor.
We have discussed sizes, target distances and types of proximity sensors, but most of
these were all round body sensors.
We also offer rectangular and rectangular harsh duty sensors like these.
They all operate on the same principles of the round
body sensors; your application will determine if you require
a round sensor or a rectangular or square sensor in order to mount the sensor to detect
your target.
Which voltage will your application require?
It depends on what you are wiring the sensor to.
Do you need AC voltage or DC voltage?
Do you need normally open or normally closed?
Will your device require the sensor to be NPN or PNP?
Do you require cables made on, or quick disconnect cables?
If the sensor is in an application where it may
get damaged periodically and will require a quick change
out, then go with quick disconnect cable styles, just don't forget to purchase the correct
cable for your sensor.
I hope this video was helpful in covering a few basics on Inductive Proximity Sensors.
Be sure to check out our other videos on sensors.
If you have any questions, please feel free to contact our award-winning technical support
team during regular business hours, they will be happy
to help.
Click on this video to learn more about AutomationDirect's support options and click here to learn more
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