Adding IR brake rotor sensor

Discussion in 'The Projects Forum' started by PLapping12, Oct 30, 2015.

  1. PLapping12

    Thread Starter New Member

    Oct 30, 2015
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    Hello all,

    First post on here. Started a project at work and am undertaking the work to learn along the way.

    So what I have is a

    http://www.texense.com/en/produits/...-ir-rotor-temp-formula-student-sensor_36.html

    sensor I am adding to our company's brake dyno. I am not an electrical engineer/electrician by trade, so please bear with me.

    I have wired the sensor as shown in the crude diagram attached. The sensor terminates in an analogue input that requires a bnc connector. I am using a binding post type bnc for the final leads.

    I have checked at the sensor and it is receiving 5vdc from my source, the signal wire is also putting out a constant voltage of about 0.156-0.160v and doesn't change at all as it should when I heat up what it is sensing (the brake rotor). I can not find anything wrong with this and have tried multiple variations of grounds and such.

    I also ran my 5vdc source straight to the binding post leads to ensure the channel is receiving correctly and the bnc is working as it should.

    Any input?
     
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    What is "TB" on your drawing?

    Also, where is your sensor connected to ground (0V)? Where is your power supply connected to 0V? They should be connected to the same 0V, right?

    In other words, you cannot just connect positive power to your sensor without completing the circuit and connecting the ground/0V to it as well.

    upload_2015-10-30_11-55-27.png
     
  3. PLapping12

    Thread Starter New Member

    Oct 30, 2015
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    Oh sorry, that means terminal block so I can eliminate the circuit if I need to.

    I have never worked with a BNC before and assumed that the ground in the BNC would ground the sensor.

    I did end up updating the wiring to this to make a more complete circuit. This is still missing a 0V for the sensor though isn't it?
     
  4. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    This drawing should work. In a 3-wire sensor like you have. The power supply goes to + and -, respectively and the sensor measures between the sense and (-). You should get a good signal now.
     
  5. PLapping12

    Thread Starter New Member

    Oct 30, 2015
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    That is what I assumed too, but it isn't working.

    I talked to someone else who wired one of these up and said they had issues with it too, and recall the word "floating ground" coming from the people hooking it up. Does that stir anything up?

    Thank you for your input!
     
  6. crutschow

    Expert

    Mar 14, 2008
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    What drawing?
     
  7. PLapping12

    Thread Starter New Member

    Oct 30, 2015
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    I believe he/she is referring to my second posted image of my wiring diagram
     
  8. strantor

    AAC Fanatic!

    Oct 3, 2010
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    Here's the datasheet. They make you give up your email address to get the DS. That's BS.
    What do you have in front of the sensor to measure?
    These IR devices are bound by the emissivity parameter; different colors of materials radiate heat differently so the sensor has to be calibrated to read objects of a certain color. Typically they come calibrated for black. If the object you're reading is shiny, or not present, who knows what the output will be. Perhaps yours came calibrated for nothing (you have to calibrate it for something before it will output anything) - although that's unlikely.
     
  9. PLapping12

    Thread Starter New Member

    Oct 30, 2015
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    My apologies, I could have attached the data sheet for you. Didn't realize it did that since ours came with our product. I will definitely look into that, but we are measuring a stainless steel rotor for temperature so I would think that would be about spot on.

    I have spot heated it what a map gas torch and also just ran engagements up to about 400*F with no luck.

    Thanks again for the suggestions, I will look to see if it was calibrated but it doesn't seem to have anything that would allow me to do it myself.
     
  10. strantor

    AAC Fanatic!

    Oct 3, 2010
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    No, it wouldn't, would it? That would be too easy. From the datasheet:
    cal.png



    Land R1200P - No price listed. If you have to ask, it's too much.
     
  11. PLapping12

    Thread Starter New Member

    Oct 30, 2015
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    Is it possible to have blown out the sensor with incorrect wiring on my initial tries? I am 100% certain it never received anything besides 5vdc, and trying to logic test it it seems if the common and live were reversed it wouldn't matter since they both can handle 5vdc, and the signal wire is a 0-5vdc so it wouldn't have mattered either correct?

    Just trying to eliminate some possibilities.

    The sensor giving off a constant 0.156-0.160v doesn't imply it is functioning does it? Since it really doesn't start measuring until 0.5v, does that imply a leak or something amiss?
     
  12. crutschow

    Expert

    Mar 14, 2008
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    It's very likely that reversing the polarity on the power leads would zap the device.
    Why do you think both leads could handle plus 5V?
     
  13. PLapping12

    Thread Starter New Member

    Oct 30, 2015
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    Not really sure why I think that (ignorance to circuits in general probably), but I am pretty positive I wouldn't have done that. Be a pretty hard thing to do.

    Is there any way to check with a multi-meter or anything, just trying to eliminate everything?
     
  14. crutschow

    Expert

    Mar 14, 2008
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    A multi-meter likely is of little help in checking the device, other than to measure the voltages when it is operating.
    If the output voltage does not seem to be correct when the proper supply voltages are applied then it likely is toast.

    Post the latest diagram of how you have it connected.
     
  15. PLapping12

    Thread Starter New Member

    Oct 30, 2015
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    My last posted picture is my current wiring. Sounds like I may have blown the sensor some how. Curious as to how though, albeit someone was tinkering with it when I was away for a little bit. Will have to ask them if it's possible the polarity got reversed at anytime. I don't think they would've done that though.
     
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