what's the difference between proximity sensor and proximity switch ? Typically what

[danishdeshmuk]

what's the difference between proximity sensor and proximity switch ?

Typically what inductive proximity sensor generates the output ? Is it a digital signal or a analog signal

If metal or metallic object is the target of inductive proximity sensor then what the output signal of inductive proximity sensor actually does ? Is it just use to switch on or switch off some device through relay normally open or through normally closed contact(s) ?

thanks

 

[iwire]

Just a guess but perhaps a sensor must be used with a controller and a switch is stand alone.

 

[steve66]

I pretty much agree with Iwire.

A switch usually has the control function built in. It just needs an input voltage, and it usually gives an on/off output.

I think a "proximity sensor" is a much less specific term. It may or may not include a power supply and/or controller. And it may have a digital output, or an anlog output, or it might be a raw sensor where the output depends on how you connect it in a circuit.

 

[petersonra]

They seem to be pretty much used interchangeably IME.

 

[eric9822]

I hear both descriptions used interchangeably. The manufacturers I use refer them to as sensors and everyone in the field calls them switches. As pointed out in previous posts some are self contained and others require external equipment depending on the type and application.

Bob beat me. That's what happens when you start a post and then get distracted.

 

[hurk27]

A sensor is a variable output device and a switch, well is a switch, its either on or off.

Look at cars, we have oil sensors and oil switch's, a sensor is used to feed a gage to show how much pressure the oil pump is producing and a switch just turns on a light on the dash that is set at a level you oil pressure should not go below, the same with the engine temp, but I have also had people mix these two up.

 

[hurk27]

To add

Proxy sensors are used with controllers or PLC's so that the measurement set points can be adjusted by the controller or PLC, where a Proxy switch has to be position at the correct measurement the equipment needs, we have both at work and they serve different purposes.

 

[danishdeshmuk]

To add

Proxy sensors are used with controllers or PLC's so that the measurement set points can be adjusted by the controller or PLC, where a Proxy switch has to be position at the correct measurement the equipment needs, we have both at work and they serve different purposes.

Ain't it that switch makes a physical contact to generate the output and sensor just sense the object or the target and then generates the output ?

thanks

 

[GoldDigger]

Ain't it that switch makes a physical contact to generate the output and sensor just senses the object or the target and then generates the output ?

thanks

If somebody told me that an assembly that used a non-contact proximity sensor to control a relay with dry contact outputs constituted a proximity switch, I might have a hard time convincing him otherwise. Except for the fact that it would require power to operate rather than being unpowered like a mechanical switch would be.
A mechanical, physical-contact, sensor that provided a resistance or other analog output would still be a sensor to me, not a switch.

A different way to look at the distinction is that a proximity switch makes a decision (fixed or adjustable), while a proximity sensor just provides data from which a decision can be made.

 

[jusme123]

1. Proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact while Proximity switches open or close an electrical circuit when they make contact with or come within a certain distance of an object.

2. The sensitivity of proximity switch can be adjusted so that the switch closes at a desired distance with a specific target, while The sensitivity of a proximity sensor would be calibrated by the manufacturer and typically would not be adjustable other than through a calibration function.

 

[GoldDigger]

1. Proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact while Proximity switches open or close an electrical circuit when they make contact with or come within a certain distance of an object.

2. The sensitivity of proximity switch can be adjusted so that the switch closes at a desired distance with a specific target, while The sensitivity of a proximity sensor would be calibrated by the manufacturer and typically would not be adjustable other than through a calibration function.

What is the source for your quote? I can find numerous other sources that do not make the same distinction. Something like UL/IEC standard 60947-5-2 would probably be the kind of source most appropriate for electrical work, yes? But I do not have a copy.

1.1 Scope and object

This part of IEC 60947 applies to inductive and capacitive proximity switches that sense the presence of metallic and/or non-metallic objects, ultrasonic proximity switches that sense the presence of sound reflecting objects, photoelectric proximity switches that sense the presence of objects and non-mechanical magnetic proximity switches that sense the presence of objects with a magnetic field.

These proximity switches are self-contained, have semiconductor switching elements(s) and are intended to be connected to circuits, the rated voltage of which does not exceed 250 V 50 Hz/60 Hz a.c. or 300 V d.c. This Standard is not intended to cover proximity switches with analogue outputs.

 

[hurk27]

I guess I have to back up a bit from my post 6, After looking at some of the proxy's we use at work most of them are in-fact a sensor even if they have a NO or NC output, I still stand that a sensor is a variable output device and a switch is a off or on device, but now that technology has reduced the size of electronic components so that a proxy sensor can include the oscillator, amplifier, and relay or output switching transistor all in the same package many proxy sensors now have the controller and output all in the same package, not many years ago this was not true as a proxy sensor had to have the controller as a separate unit.

But how the sensor operates is still the same, the heart of the sensor provides a variable output to an amplifier that is used to switch a switching transistor which can drive a relay for a dry contact output, or it doesn't have the relay but still has the switching transistor which can switch a load depending on NPN or PNP that can be used to control a PLC input signal either pull up or pull down input.

Or leave out the switching transistor and have a variable output such as but not limited to a 4-20ma or 0-10v PID output that a controller or PLC can use to make and change set points to adjust the the point of change you want or need, these are called Analog & Linear outputs.

But the heart of a proxy sensor is the fact that it does provide a variable voltage or current to a amplifier that can be used for your control, the fact that a certain models might also have the controller with a relay on-board with adjustments to change the point it switches the relay or changes the sensitivity does not change this and is why we see these still being called sensors and not switch's.

When I hear proximity switch the first thing I think of is the old magnetic reed switch's that had a small magnet on the read switch that came in just a few types NO and NC or both, these were nothing more then a switch, and was very common type used for alarm circuits on doors or windows that can slide to open, there are also some that use electronics to provide the same results but are basically the same, they have no variable output they are either open or closed NO or NC.

As to post 10 (jusme123)

No most proxy sensors have adjustment depending on its design and model can have many adjustments and some can even have time delays to prevent false on or offs, these are all in one sensors with the controller built in and package and a single mountable unit.

Also any switch that has to make physical contact with the item it is used for is nothing but a limit switch, while a limit switch can be used as a proxy switch for position it is not defined as a proxy switch as it does make contact which a true proxy switch as the name implies only has to be in proximity of the item that is being detected, simply a proxy switch or sensor is a limit switch that doesn't make contact with the item it is monitoring.

There are many types of proxy sensors and the use for them is endless, from the wire embedded in the road to detect cars that make the signal light change or prevent an automatic gate closer from closing on a car, to an IR laser reflected off a target that determines the distance to the target for laser guided missiles, you have four basic types of proximity sensors: infrared, acoustic, capacitive, and inductive but there are others including radio wave systems.

 

[topgone]

what's the difference between proximity sensor and proximity switch ?

Typically what inductive proximity sensor generates the output ? Is it a digital signal or a analog signal

If metal or metallic object is the target of inductive proximity sensor then what the output signal of inductive proximity sensor actually does ? Is it just use to switch on or switch off some device through relay normally open or through normally closed contact(s) ?

thanks

A proximity sensor is either an inductive or capacitive type. The sensor face "senses" the presence of something that is "near" it. The sensor needs to be supplied with a voltage (AC or DC, as the sensor type demands) and the "output" of the sensor is either a "close" or "open" contact. There are two types of connections sensor designs that I have dealt with:

1. two-wire design - where control supply line 1 is connected to one leg of the sensor terminal and the other leg of the sensor terminal is routed to a relay coil and the opposite relay coil terminal returns to the control supply line 2. (the sensor is in series with the relay coil supplied by the auxiliary control voltage). Or the sensor output is supplied to a speed monitor input terminals (one from the sensor leg and the other connected straight to the line 2 of control supply.
2. three-wire design - where the sensor is supplied on both terminals and the third wire gets to pair with the line 2 that could energize a relay coil or be fed to a speed monitor device. This design is superior to the two-wire due to a small voltage drop that is needed in the 2-wire design for firing up the sensor circuitry.

Bluntly, both the proximity switch and the proximity sensor acts like a switch that activate when something is in the vicinity. The proximity switch is a contact device while the proximity sensor is a non-contact device. The speed monitor mentioned merely counts the number of pulses the sensor feeds and does its speed calculation internally by proper selection of settings in the monitor.

Hope that clears this matter.

 

[GoldDigger]

Bluntly, both the proximity switch and the proximity sensor acts like a switch that activate when something is in the vicinity. The proximity switch is a contact device while the proximity sensor is a non-contact device. The speed monitor mentioned merely counts the number of pulses the sensor feeds and does its speed calculation internally by proper selection of settings in the monitor.

Hope that clears this matter.

I think that there have been enough examples so far to indicate that a proximity switch will not necessarily (or at all) be a contact device. That would make it a limit switch rather than a proximity switch.
FWIW, a device which senses proximity (note that I am copping out and not calling it a proximity sensor) could also use a light beam, ultrasonic distance measurement, or even arguably be a reed switch and a magnet, among other possibilities.

I don't think we are going to reach any kind of consensus in this discussion, except maybe that it all depends on the context in which the words are used. Different contexts rely on different definitions and authorities, so IHMO the real question goes back to asking the OP what the context is.