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  1. #14
    Join Date
    Jun 2009
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    StL, MO
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    This can be done with kitControl math blocks and a little help from excel's Trendline feature. Copy and paste the temperature vs pressure values in to excel. Convert to PSIA and Deg R (curve fitting works better). Create a graph and try the various Trendlines until you get a good fit. I came up with this for R134a. y = 0.00003561 x^3 - 0.01308796 x^2 + 2.12259171 x + 421.11910836 With x = PSIA and a range of 20.7 to 149.7 and y = deg R.
    Name:  R134a.jpg
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    UA LU 562

  2. #15
    Join Date
    Jul 2010
    Location
    Az
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    Could I get a copy of the program objects also, email is in my profile, Thank you.

  3. #16
    Join Date
    Jul 2008
    Location
    Melbourne
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    Quote Originally Posted by DaveCR View Post
    I came up with this for R134a. y = 0.00003561 x^3 - 0.01308796 x^2 + 2.12259171 x + 421.11910836 ]
    nice work ... though I think it maybe time to make a generic curve-fit Program Object to the 4th or 5th order.

    ...maybe even have an Enum setting for different refrigerants
    1 + 1 = 3 ( *** for very large values of 1)

    ...everybody wants a box of chocolates and long stemmed rose

    Be brave. You cannot get eaten by an imaginary tiger.

  4. #17
    Join Date
    Jun 2009
    Location
    StL, MO
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    Thanks. For 134a:
    y = 9.20621E-10 x^5 - 6.26875E-07 x^4 + 1.65989E-04 x^3 - 2.26106E-02 x^2 + 2.14070E+00 x - 1.32707E+01
    Input pressure range (PSIA) 14.7 to 244.7. Output °R. This turns out to be quite a good fit with R squared = 0.9999
    Last edited by DaveCR; 01-27-2013 at 11:44 AM. Reason: punctuation
    UA LU 562

  5. #18
    Join Date
    Mar 2007
    Posts
    437
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    Quote Originally Posted by DaveCR View Post
    This can be done with kitControl math blocks and a little help from excel's Trendline feature. Copy and paste the temperature vs pressure values in to excel. Convert to PSIA and Deg R (curve fitting works better). Create a graph and try the various Trendlines until you get a good fit. I came up with this for R134a. y = 0.00003561 x^3 - 0.01308796 x^2 + 2.12259171 x + 421.11910836 With x = PSIA and a range of 20.7 to 149.7 and y = deg R.
    Name:  R134a.jpg
Views: 706
Size:  42.4 KB
    I've been attempting to set this up all morning for R410A and I can't seem to figure out for the life of me how to get it to output properly. I know lynxspring has an actual conversion block in their lynxKitControl, but unfortunately it only works with their certificate on the JACE.

    Anyone else sucessfully made this work for 410?
    Friends don't let friends Lon.

  6. #19
    Join Date
    Jan 2002
    Location
    Fort Worth\Dallas, Texas
    Posts
    1,791
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    Quote Originally Posted by noskilltech View Post
    I've been attempting to set this up all morning for R410A and I can't seem to figure out for the life of me how to get it to output properly. I know lynxspring has an actual conversion block in their lynxKitControl, but unfortunately it only works with their certificate on the JACE.

    Anyone else sucessfully made this work for 410?
    I have a program object for 134 that you could probably change the pressure-temp tables in for 410.
    Go Rangers!

  7. #20
    Join Date
    Mar 2007
    Posts
    437
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    I'll send you an email here in just a second. Thanks
    Friends don't let friends Lon.

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