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George,<br>
I would think that if you are getting negative values in the
interpolation of data that is always positive, there might be an
incorrect setting as to the nature of the data. Type9 asks you to
specify various things about your data. For example: whether or not
there is a line of initial values at the beginning of the data file,
whether the values in your data file are instantaneous values at the
end of the data interval or whether they are average values over the
interval, and whether or not you want the values to be interpolated.
The Type9 "mode" can also have an impact. I often play around with
these values until the outputs that Type9 are producing (plotted
with Type65) match up with the data that is going in.<br>
<br>
One "cheap and dirty" fix would be to put Type9's outputs through
an equation as follows:<br>
<br>
posVals = MAX(0.,Type9Output)<br>
<br>
but officially, you did not hear me suggest that... :-)<br>
<br>
best,<br>
David<br>
<br>
<br>
On 12/12/2011 09:54, George Kyriakarakos wrote:
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<title>Data Reader interpolation question</title>
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<p dir="LTR"><span lang="en-us"><font face="Calibri">Dear</font></span><span
lang="en-us"> <font face="Calibri">all</font></span><span
lang="en-us"><font face="Calibri">,</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">I have some
hourly electrical consumption data (unit is kW). I want to
do some simulations with low time</font></span><span
lang="en-us"></span><span lang="en-us"> <font face="Calibri">step
(eg.</font></span><span lang="en-us"> <font face="Calibri">0.05)
in order to check a controller</font></span><span
lang="en-us"><font face="Calibri"> I have designed</font></span><span
lang="en-us"><font face="Calibri">. When I try that at some
time</font></span><span lang="en-us"></span><span
lang="en-us"> <font face="Calibri">steps I get negative
values of load</font></span><span lang="en-us"><font
face="Calibri">, because of big changes</font></span><span
lang="en-us"><font face="Calibri"> in the data</font></span><span
lang="en-us"><font face="Calibri"> from one hour to the other</font></span><span
lang="en-us"><font face="Calibri">. I understand why this
happens, but of course I cannot use this</font></span><span
lang="en-us"><font face="Calibri">. Is there any way using
standard types to interpolate data keeping in mind that the
result ought to be positive? Of course I can write a new
type, but I would rather not go down that road.</font></span><span
lang="en-us"></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Thanks in
advance,</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">George</font></span><span
lang="en-us"></span></p>
<p dir="LTR"><span lang="en-us"></span><span lang="el-gr"><font
face="Calibri">-------------------------------------------------------------------</font></span></p>
<p dir="LTR"><span lang="el-gr"><font face="Calibri">George
Kyriakarakos, Agricultural Engineer</font></span></p>
<p dir="LTR"><span lang="el-gr"><font face="Calibri">MSc Energy
Systems & Renewable Energy Sources</font></span></p>
<p dir="LTR"><span lang="el-gr"><font face="Calibri">Agricultural
University of Athens,</font></span></p>
<p dir="LTR"><span lang="el-gr"><font face="Calibri">Dept. of
Natural Resources and Agricultural Engineering</font></span></p>
<p dir="LTR"><span lang="el-gr"><font face="Calibri">Iera odos
street, 75, Athens 11855, Greece</font></span></p>
<p dir="LTR"><span lang="el-gr"><font face="Calibri">Tel.
+30.210.5294046 (direct), Fa</font><font face="Calibri">x:
+30.210.5294023</font></span></p>
<p dir="LTR"><span lang="en-us"></span><span lang="el-gr"></span><span
lang="el-gr"><font face="Calibri">Mobile +30.6942.046895</font></span></p>
<p dir="LTR"><span lang="el-gr"><font face="Calibri">e-mail: <</font></span><span
lang="en-us"></span><a moz-do-not-send="true"
href="mailto:gk@aua.gr"><span lang="en-us"></span><u><span
lang="el-gr"></span></u><u><span lang="el-gr"><font
color="#0000FF" face="Calibri">gk@aua.gr</font></span></u><span
lang="en-us"></span></a><span lang="en-us"></span><span
lang="el-gr"></span><span lang="el-gr"><font face="Calibri">></font></span></p>
<p dir="LTR"><span lang="el-gr"><font face="Calibri">--------------------------------------------------------------------</font></span></p>
<p dir="LTR"><span lang="en-us"></span><span lang="el-gr"></span></p>
<p dir="LTR"><span lang="en-us"></span></p>
<br>
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