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aaronik19
Joined: 25 Apr 2011 Posts: 297
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Capacitive Proximity Sensor |
Posted: Thu Dec 22, 2016 10:04 am |
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Dear All,
I am making a design and I am looking for a Capacitive Proximity Sensor with external sensitivity trimming (not the one on the sensor) since the sensor will be mounted 20 meters high on a conveying pipe.
Do you ever used such sensor? I am also interesting to build this sensor as well in case it is not available, but the problem is where I can buy the plates of the capacitance sensor? Can I use Touch Sensor breakout board to sense powder product in a conveying pipe?
Thanks for your help |
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newguy
Joined: 24 Jun 2004 Posts: 1903
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Posted: Thu Dec 22, 2016 12:07 pm |
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I'd be inclined to say that in order to get repeatable results, you're going to need some precision with your prototype sensing plates. In my mind, that means a custom PCB just for the sensing elements. You can prototype using almost anything as your capacitive sensing plate(s), but when you try to move the design to something final/"nice", you're going to have issues. |
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temtronic
Joined: 01 Jul 2010 Posts: 9173 Location: Greensville,Ontario
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Posted: Thu Dec 22, 2016 12:52 pm |
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this...
the sensor will be mounted 20 meters high on a conveying pipe.
probably is not going to work well...
20meters=60feet+-, 'noisy' industrial environment...dirt,EMI,humidity, etc...all factors in cap sensor tek.
Would need to know more about the 'environment' but I'm inclined to use a slave PIC, run RS485 and power from the 'master' PIC. Better yet some form of cabling/comm tech that KNOWS when the cables cut.....
Jay |
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Mike Walne
Joined: 19 Feb 2004 Posts: 1785 Location: Boston Spa UK
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Re: Capacitive Proximity Sensor |
Posted: Thu Dec 22, 2016 3:22 pm |
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aaronik19 wrote: | Dear All,
I am making a design and I am looking for a Capacitive Proximity Sensor with external sensitivity trimming (not the one on the sensor) since the sensor will be mounted 20 meters high on a conveying pipe.
Do you ever used such sensor? I am also interesting to build this sensor as well in case it is not available, but the problem is where I can buy the plates of the capacitance sensor? Can I use Touch Sensor breakout board to sense powder product in a conveying pipe?
Thanks for your help | You're being far too vague.
What is the nature of the powder?
How big is the pipe?
How fast is the powder moving?
How is the powder being moved through the pipe?
Have you considered any other kind of sensor?
the list goes on...................
We need loads more information before we can even start to try to help you.
Mike |
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aaronik19
Joined: 25 Apr 2011 Posts: 297
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Posted: Thu Dec 22, 2016 4:09 pm |
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At the moment we are using the IFM capacitive sensors http://www.ifm.com/products/gb/ds/KI5083.htm and is working perfectly but the problem is that once it is connected, it is very hard to adjust sensitivity in case it loses the tuning due to product change. The power is being conveyed using an air blower pressure of 500mBar and flow rate of 5000m3/h.
I am looking for something that in case sensitivity need to be tuned, it can be done from a control panel. |
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Ttelmah
Joined: 11 Mar 2010 Posts: 19366
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Posted: Fri Dec 23, 2016 2:07 am |
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Not with that sensor.
There are several manufacturers who do smart sensors where you can program the trigger point, or you use a simple analog output sensor, and program the reference voltage remotely. Or just design your own based on one of the 8pin PIC's with capacitive sensing built in, and have a serial connection to program the level.
Do a search for Efector150 and Efector160. These include models, where the zero point can be programmed remotely by a pulse on the programming wire. They also have a slightly better detector design, making them more immune to drift.
Talk to Ifm (the manufacturer of the above). If I remember correctly, they were even offering Internet programmable versions.
You make the plates in the PCB inside the casing. Design affects the sensing region shape. Also using multi-layer boards allows you to reduce the effects in different directions. Lots of work learning about capacitance.....
What is strange is that you are using the 'dumb' version from the same manufacturer. One 'rule' is 'talk directly to the technical people' for this sort of question. Generally manufacturers want you to use their products, and will be quick to tell you that they do a smarter version that can help!...
For a 'smart' sensor, look at the Gill GS4223. Has two outputs and serial. You can program an output to be a level switch, and configure what fluid you are sensing, and the level you want to switch at. |
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