# Niagara AX- Need a Pressure Temperature Conversion block

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• 01-24-2013, 06:23 PM
DaveCR
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.
Attachment 349691
• 01-24-2013, 11:50 PM
22nomo
Could I get a copy of the program objects also, email is in my profile, Thank you.
• 01-25-2013, 03:17 AM
MatrixTransform
Quote:

Originally Posted by DaveCR
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
• 01-27-2013, 11:42 AM
DaveCR
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
• 08-18-2016, 01:49 PM
noskilltech
Quote:

Originally Posted by DaveCR
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.
Attachment 349691

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?
• 08-18-2016, 02:16 PM
lwarren
Quote:

Originally Posted by noskilltech
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.
• 08-18-2016, 02:41 PM
noskilltech
I'll send you an email here in just a second. Thanks
• 09-22-2017, 01:26 PM
AutomatedFreak
Does anyone have a program object for refrigerant pressure temperature (R410a) ?