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BlurDavinci

Angle Measurement Transducer

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Hi: I'm looking for a device to measure angle relative to one plane and it should be contactless. Example If I placed a piece of straight bar at an angle from a flat surface, how do I get the angle?

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If you know the length of the bar and the distance from the end of the bar to the plane, that would give you two sides of a triangle and you could use trigonometry to find the angle.

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how about two distance measurment devices at a known distance from each other? depending on required accuracy you can use ultasonic or laser. you could calc the difference between them and with that and the distance between you could trig the angle.

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I Googled 'electronic angle measurement' and got a number of appropriate hits. Also try 'tilt meter'

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Angle measurement is called an "inclinometer". It is meant for rotating shafts, but a company called Electro Sensors makes a nice sealed unit with a 4-20mA output. There are a huge variety of others. The interfaces are generally SSI, RS-232, or discrete outputs (like gray coded), which makes the number of wires generally kind of a pain, depending on the application. Otherwise as suggested, use trig and distance sensors.

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pabeader: I'm interested with your suggestion but i do not know what is the appropriate type, can you be more specific on the ultrasonic or laser device? Thanks

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what kind of range, target material, target size, speed and accuracy you are expecting? ultrasonic and laser sensors can be used for measuring distance without making contact with the target. we use lasers a lot as they are dead simple to aim, not nearly as sensitive to material properties as ultrasonic (doesn't matter if target is concrete, steel, sponge or single sheet of tissue paper flying in the air), they are also very robust (not sensitive to interference or ambient). if you have more than one ultrasonic sensor, they must be interlocked somehow (usually they have special wire for syncing of two sensors etc.). for example i was just using four Baumer sensors OADM12U6460/S35A aimed straight at each other (like a cross) and working simultaneously (and continuously) on what seam to be similar to your project: part that was passing through was usually round but with different diameters and different points. surface was shiny metal (mirror like) ranging from smooth to small threaded channels from machining (0.5mm or so) and of course there ware gaps between parts so sensors would look into each other (we had encoder for position of passing part and we had to detect the edges since all measurements ware related to this plane). part is long and can be tilted in any direction (withing few degrees) so one aim was to position machine on fly according to passing part - without ever touching it (keep machine center both coaxial and parallel with the passing round object). we needed fairly high accuracy and in very tight space. fortunately this was moving only few inches per second...

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I usually end up ignoring laser and photoelectric and going for ultrasonic for dust reasons. It also has the annoying feature of beam spread and it is affected by air temperature...both of which are nonexistent with laser for the most part. In the "clean" part of the plant where I work at, lasers were a disaster when used on the product because it is painted flat black...hard to get a reliable return signal off it. However in a clean environment and with the appropriate materials, laser is far simpler.

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Panic mode, Please, elaborate on this paragraph. We have application where we are planning to use two analog ultrasonic sensors, Baumer UNDK 30U6103. Each sensor will measure distance to its object. Both of these sensors will not be pointed to each other. But they will be close to each other (12-18 inch). Do you know if they will affect each other measurements. Thank you, PaulB

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you really need to talk to your sensor supplier/manufacturer about your application and do some testing before project is complete, ask for sample and/or demonstration. ultrasonic sensors simply use echo to detect the presence of target and/or distance. if there is sound or noise of right frequency (like same type of sensor or simply reflection of the own signal) it is possible that sensor will get confused and provide incorrect output ("if it quacks like a duck..."). crude way of selecting sensor is by powering one at a time and of course obvious problem penalties in response due settling time (it takes some time, even if short, to powerup, take the reading and stabilize). one common method in reducing sensitivity to ambient noise is using higher frequency (usually hundreds of kHz) but this still doesn't eliminate interference between two or more of same kind of a sensors in case they are not far from each other. you still have to consider cone size, distance between the sensors, reflection surfaces, beam paths etc. this makes use of more than one ultrasonic sensor often rather complicated. at least in my projects, there is usually tons of sensors. (just the test station will have anything from 50-150 sensors and that's in the space not larger than common TV set.) but when just one ultrasonic sensor simply doesn't cut it, things like syncronization come into play. many ultrasonic sensors will have "sync" or "control" wire or whatever they call it. this allows both sensors to remain powered and take measurements at the "same" time (like in crude method, only faster...). same thing is sometimes seen on other devices such as light curtains etc. http://www.baumerelectric.com/en/40.asp#Synchronization http://www.baumerelectric.com/en/40.asp#Multiplexoperation particular sensor you plan on using seam to be 3-wire device (no control wire) http://www.baumerelectric.com/en/shop/cata...rch=UNDK30U6103

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Depending on what you are trying to do. Here are LED based distance measurement devices. Banner models Q50AVI and Q50AVU They also have laser based one for longer distance or greater accuracy. Hope the attached image is helpful. Edited by pabeader

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You might want to look at lucas schaevitz sensors. I am familiar with their RVIT-15-60/RVIT-15-120I RVITs model. They're extremely rugged contactless angle transducers that will supply a voltage or current signal...

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