transducer wiring to digital read out

Discussion in 'General Electronics Chat' started by bomrat, Mar 26, 2014.

  1. bomrat

    Thread Starter New Member

    Dec 13, 2009
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    hi, i have a transducer , it is 24v in, 1-6vdc out.
    i wire the transducer to the power and check output with a multimeter and i get the .98v on the output leg, if i put the digital readout on gnd and the output leg it won't display. do i need a resistor inline? and if so what value, 10k?
    thanks
     
  2. strantor

    AAC Fanatic!

    Oct 3, 2010
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    Transducer part number? Display part number? Quick draw a wiring diagram?
     
  3. bomrat

    Thread Starter New Member

    Dec 13, 2009
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    hi, heres the drawing
    thanks
     
  4. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    The one time I worked with pressure transducer, the part info mentioned 5 kOhm or greater load, but I did not really pay attention because I had it hooked up to op-amp which by its nature has really high input resistance so I assumed that transducer was seeing a really large resistor load.

    Bottom line. Check transducer info for what it needs or contact manufacturer.
     
  5. strantor

    AAC Fanatic!

    Oct 3, 2010
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    Transducer part number?
     
  6. bomrat

    Thread Starter New Member

    Dec 13, 2009
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    keller pa=21sr transducer
     
  7. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    like this

    you need to put 5 bar pressure on it to get it to work.
     
    Last edited: Mar 26, 2014
  8. bomrat

    Thread Starter New Member

    Dec 13, 2009
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    ok ill try that
    thankns
     
  9. strantor

    AAC Fanatic!

    Oct 3, 2010
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    Where do you see that info? The datasheet for the PA21SR shows that it comes in several ranges from 1 to 600 bar. Overpressure limit for the 1 bar model is 3 bar. Hopefully OP will check his model/rating before applying 5 bar.

    It sounds like you're bench testing (no pressure applied to transducer) so .98V is correct and should be expected from a transducer with specified 1-6V range.

    Your drawing shows a two-wire "LCD readout 0-30VDC" meter from MPJA.com. I could not find a two wire digital meter on MPJA.com with those specs, and I seriously doubt that such a thing exists. A digital meter must have sufficient voltage to power itself before it can measure anything. It is more likely that you have one of the only (2) two-wire digital 30V meter models offered by MPJA; the larger 4.5-30VDC meters, in red, blue, and green, or the smaller 3.5-30VDC model in red, blue, and green.

    You need to be using a 3 wire meter like this.
     
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