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Pressure Sensor for water level measurement

Discussion in 'General Electronics Chat' started by premkumar9, Apr 1, 2015.

  1. alec_t

    alec_t Well-Known Member Most Helpful Member

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    I have no way of knowing.
     
  2. alec_t

    alec_t Well-Known Member Most Helpful Member

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    One of these (except this one has instructions)?
    Sensor.gif
     
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  3. premkumar9

    premkumar9 Member

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    Not like that. Why it is not working and can it be used.
     
  4. dave

    Dave New Member

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  5. premkumar9

    premkumar9 Member

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    Is there any tests I can do here to confirm that?
     
  6. premkumar9

    premkumar9 Member

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    I mean why the voltage output is not stable and whether this sensor can be used for my application. These are the questions for which I try to find answer. Not "we bought this, make it work". That is only your interpretation :D
     
  7. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    Link to sensor datasheet please. I can't seem to find it in this thread. Just eric's.
     
  8. Tony Stewart

    Tony Stewart Well-Known Member Most Helpful Member

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  9. alec_t

    alec_t Well-Known Member Most Helpful Member

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    See post #48.
     
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  10. premkumar9

    premkumar9 Member

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    Ok:)
     
  11. Tony Stewart

    Tony Stewart Well-Known Member Most Helpful Member

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    I've been there a few times in the '70s when I worked for Bristol Aerospace launching Black Brandt Rockets.

    I also experienced this while trying to drive back from the Research Range back into Churchill.

    " If you can't see the rock in front of you in full daylight, it's a white-out"

    My 1st design of a Doppler Tracking system with an ultra stable OCXO PLL subcarrier on telemetry worked for tracking rocket position from subcarrier drift with frequency> 1e-10

    My last design failed after I left for a better job, but it worked in the lab. It was a HP9825 dual calc SCADA 200 channel A/D remote control system for ground control of Rockets. The problem they failed to solve was Short Wave interference with RS485 1km link. All it needed was a CM choke and RF caps.
     
  12. premkumar9

    premkumar9 Member

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    I had the temperature sensor readings also .If you see any anomalies , I will arrange the readings again. The Air Conditioner in the room was intermittently switched ON and OFF. My work place is shifted and it may take some more time to fix this set up as the new place doesn't have sufficient height (due to false ceiling) to fix the pipe.:)
    upload_2015-4-23_6-57-48.png
     
  13. JimB

    JimB Super Moderator Most Helpful Member

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    Prem, if you have this data in Excel, try plotting the values on a graph.
    It looks quite interesting, I am not sure what it proves but I think it is interesting.

    JimB
     
  14. Tony Stewart

    Tony Stewart Well-Known Member Most Helpful Member

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    AS it turned out that only took me a few minutes Temperature Correlation is indeed useful for improving the accuracy.

    upload_2015-4-23_1-25-9.png
     
  15. premkumar9

    premkumar9 Member

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    I am unable to find any relationship between temp , water sensor and ref sensor output variations :(
     
  16. Tony Stewart

    Tony Stewart Well-Known Member Most Helpful Member

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    There is obviously other sources of error below 1047, but above 1047, the correction factor is a linear relation.

    i wish you could get a more accurate reference and analyze your errors.
     
  17. premkumar9

    premkumar9 Member

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    The ADC is not coming to picture. I am taking direct voltage readings.
     
  18. Tony Stewart

    Tony Stewart Well-Known Member Most Helpful Member

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    AS I said before the reference is the Bandgap reference voltage in both DMM and ADC needs to be temperature stable. <<+-1 deg C

    E.g. with some effort , you can make a 1V stable reference, then you could subtract this and measure in a lower scale and improve accuracy.
    Then you could investigate RF effects by putting on a small RF cap and observe and many more things. This is getting repetitious.
     
  19. premkumar9

    premkumar9 Member

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    As I mentioned before, my test set up is disturbed due to office shifting. Once it is set up, I will start my testing again. All the valuable suggestions I got through this forum will be tried out then.:)
     
  20. Tony Stewart

    Tony Stewart Well-Known Member Most Helpful Member

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    Even without an office , you can order parts and get delivered make a 1V programmable zener reference with heater R and thermistor in a mini-over and operate at a fixed Temp just above ambient max. with styrafoam insulation, it can heat up in 15 seconds and be stable. We used this method for testing crystal temperature cooeficients to calibrate within 1ppm. Material cost was < 1 hr salary. Got a budget?
     
  21. JimB

    JimB Super Moderator Most Helpful Member

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    Now that I have had some sleep, here is my graph:

    Water depth.JPG


    The time of day is on the X axis.
    The 50m PTX is the blue trace
    The external PTX is the red trace
    The temperature TX is the yukky green trace.

    All values have been normallised to "per unit", of the values at 14:15.

    JimB
     
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