Re: Quantisation issues - how do i get the math right?

Tobias Oetiker <[email protected]> Fri, 10 Mar 2017 16:42:18 +0100 (CET)
Newsgroups gmane.comp.db.rrdtool.user
Message-ID <[email protected]>
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Hi Andreas 

ah it is a counter ... then you use COUNTER ... I thought you had something detecting events ... then you could use update to 'load' and event into the rrd. 

cheers 
tobi 

----- On Mar 10, 2017, at 4:37 PM, Andreas Schuldei <[email protected]> wrote: 

> I changed that and am puzzled.
> how do i deal with the huge offset? In that setup, the value the device returns
> is ~8000, and its a 64bit counter...

> in an other thread ( [
> https://lists.oetiker.ch/pipermail/rrd-users/2014-September/020015.html |
> https://lists.oetiker.ch/pipermail/rrd-users/2014-September/020015.html ] )
> that seems to deal with a similar issue, someone recommend:

> "Alternatively, you could use Absolute and reset the counter each time - then
> you don't need to worry about storing the total."

> I can not reset the counter in the device. Or is that some rrdtool counter that
> i can reset with some clever CDEF magic?

> And how will the data, which "absolute" would give me, be usable in my case?
> from the documentation ( [
> https://oss.oetiker.ch/rrdtool/tut/rrd-beginners.en.html |
> https://oss.oetiker.ch/rrdtool/tut/rrd-beginners.en.html ] ) i understand i
> would get an slowly ascending staircase. But in what way can i use that to
> emulate my incoming power? ever increasing power from my solar panels would be
> awesome, but that is not what I experienced before using rrdtool :-)

> On Fri, Mar 10, 2017 at 3:10 PM Tobias Oetiker < [ mailto:[email protected] |
> [email protected] ] > wrote:

>> if you have 'pulses' use the ABSOLUTE DS type ...

>> and the multiply the result by whatever a pulse is worth

>> cheers
>> tobi

>> ----- On Mar 10, 2017, at 2:46 PM, Andreas Schuldei < [
>> mailto:andreas%[email protected] | [email protected] ] > wrote:

>>> This is a graph i get with my current intake of sun and my setup, consisting of
>>> thermo sensors on in- and outgoing water pipes, as well as a water meter,
>>> emitting S0 impulses, indicating that 10l of fluid were pumped.
>>> My Issue is with dealing with the impulses in a sensible way. The interval of
>>> these impulses varies, depending on the sun intake.

>>> currently my CDEF for the solar power is
>>> d,c,-,a,*,10,*,4.190,*
>>> where c and d are my temperatures, and a is my counter, indicating 10 liters.
>>> (4.190 is the specific heat constant of water.)

>>> Now what is calculated by that CDEF is not really the solar power, its the
>>> momentary value, only, calculated for the duration of the impulse, which is the
>>> width of my sampling rate (which is 10sec). it would have been more accurate to
>>> take the time between the impulses and calculate the incoming energy during
>>> that period, divided by the duration of that time and graph that for the
>>> previous (or following) interval.

>>> How can I do that?

>>> _______________________________________________
>>> rrd-users mailing list
>>> [ mailto:[email protected] | [email protected] ]
>>> [ https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users |
>>> https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users ]

>> --
>> Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland
>> [ http://www.oetiker.ch/ | www.oetiker.ch ] [ mailto:[email protected] |
>> [email protected] ] [ tel:+41%2062%20775%2099%2002 | +41 62 775 9902 ]

-- 
Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland 
www.oetiker.ch [email protected] +41 62 775 9902 

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<html><body><div style=3D"font-family: arial, helvetica, sans-serif; font-s=
ize: 12pt; color: #000000"><div>Hi Andreas</div><div><br data-mce-bogus=3D"=
1"></div><div>ah it is a counter ... then you use COUNTER ... I thought you=
 had something detecting events ... then you could use update to 'load' and=
 event into the rrd.</div><div><br data-mce-bogus=3D"1"></div><div>cheers</=
div><div>tobi</div><div><br></div><span id=3D"zwchr" data-marker=3D"__DIVID=
ER__">----- On Mar 10, 2017, at 4:37 PM, Andreas Schuldei &lt;andreas@schul=
dei.org&gt; wrote:<br></span><div data-marker=3D"__QUOTED_TEXT__"><blockquo=
te style=3D"border-left: 2px solid #1010FF; margin-left: 5px; padding-left:=
 5px; color: #000; font-weight: normal; font-style: normal; text-decoration=
: none; font-family: Helvetica,Arial,sans-serif; font-size: 12pt;" data-mce=
-style=3D"border-left: 2px solid #1010FF; margin-left: 5px; padding-left: 5=
px; color: #000; font-weight: normal; font-style: normal; text-decoration: =
none; font-family: Helvetica,Arial,sans-serif; font-size: 12pt;"><div dir=
=3D"ltr">I changed that and am puzzled.&nbsp;<div>how do i deal with the hu=
ge offset? In that setup, the value the device returns is ~8000, and its a =
64bit counter...</div><br><div>in an other thread (<a href=3D"https://lists=
.oetiker.ch/pipermail/rrd-users/2014-September/020015.html" target=3D"_blan=
k">https://lists.oetiker.ch/pipermail/rrd-users/2014-September/020015.html<=
/a>) that seems to deal with a similar issue, &nbsp;someone recommend:</div=
><br><div>"Alternatively, you could use Absolute and reset the counter each=
 time - then you don't need to worry about storing the total."&nbsp;</div><=
br><div>I can not reset the counter in the device. Or is that some rrdtool =
counter that i can reset with some clever CDEF magic?</div><br><div>And how=
 will the data, which "absolute" would give me, be usable in my case? from =
the documentation (<a href=3D"https://oss.oetiker.ch/rrdtool/tut/rrd-beginn=
ers.en.html" target=3D"_blank">https://oss.oetiker.ch/rrdtool/tut/rrd-begin=
ners.en.html</a>) i understand i would get an slowly ascending staircase. B=
ut in what way can i use that to emulate my incoming power? ever increasing=
 power from my solar panels would be awesome, but that is not what I experi=
enced before using rrdtool :-)</div><br></div><br><div class=3D"gmail_quote=
"><div dir=3D"ltr">On Fri, Mar 10, 2017 at 3:10 PM Tobias Oetiker &lt;<a hr=
ef=3D"mailto:[email protected]" target=3D"_blank">[email protected]</a>&gt; wro=
te:<br></div><blockquote class=3D"gmail_quote" style=3D"margin: 0 0 0 .8ex;=
 border-left: 1px #ccc solid; padding-left: 1ex;" data-mce-style=3D"margin:=
 0 0 0 .8ex; border-left: 1px #ccc solid; padding-left: 1ex;"><div class=3D=
"gmail_msg"><div style=3D"font-family: arial,helvetica,sans-serif; font-siz=
e: 12pt; color: #000000;" class=3D"gmail_msg" data-mce-style=3D"font-family=
: arial,helvetica,sans-serif; font-size: 12pt; color: #000000;"><div class=
=3D"gmail_msg">if you have 'pulses' use the ABSOLUTE DS type ...&nbsp;</div=
><div class=3D"gmail_msg"><br class=3D"gmail_msg"></div><div class=3D"gmail=
_msg">and the multiply the result by whatever a pulse is worth</div><div cl=
ass=3D"gmail_msg"><br class=3D"gmail_msg"></div><div class=3D"gmail_msg">ch=
eers</div><div class=3D"gmail_msg">tobi</div></div></div><div class=3D"gmai=
l_msg"><div style=3D"font-family: arial,helvetica,sans-serif; font-size: 12=
pt; color: #000000;" class=3D"gmail_msg" data-mce-style=3D"font-family: ari=
al,helvetica,sans-serif; font-size: 12pt; color: #000000;"><div class=3D"gm=
ail_msg"><br class=3D"gmail_msg"></div><div class=3D"gmail_msg"><br class=
=3D"gmail_msg"></div><span id=3D"m_-403608630817418923zwchr" class=3D"gmail=
_msg">----- On Mar 10, 2017, at 2:46 PM, Andreas Schuldei &lt;<a href=3D"ma=
ilto:andreas%[email protected]" class=3D"gmail_msg" target=3D"_blank">=
[email protected]</a>&gt; wrote:<br class=3D"gmail_msg"></span><=
/div></div><div class=3D"gmail_msg"><div style=3D"font-family: arial,helvet=
ica,sans-serif; font-size: 12pt; color: #000000;" class=3D"gmail_msg" data-=
mce-style=3D"font-family: arial,helvetica,sans-serif; font-size: 12pt; colo=
r: #000000;"><div class=3D"gmail_msg"><blockquote style=3D"border-left: 2px=
 solid #1010ff; margin-left: 5px; padding-left: 5px; color: #000; font-weig=
ht: normal; font-style: normal; text-decoration: none; font-family: Helveti=
ca,Arial,sans-serif; font-size: 12pt;" class=3D"gmail_msg" data-mce-style=
=3D"border-left: 2px solid #1010ff; margin-left: 5px; padding-left: 5px; co=
lor: #000; font-weight: normal; font-style: normal; text-decoration: none; =
font-family: Helvetica,Arial,sans-serif; font-size: 12pt;"><div dir=3D"ltr"=
 class=3D"gmail_msg"><img pnsrc=3D"cid:15ab85d652567b157151" alt=3D"drraw.p=
ng" style=3D"max-width: 100%; opacity: 1;" class=3D"gmail_msg" data-mce-sty=
le=3D"max-width: 100%; opacity: 1;" src=3D"cid:15ab85d652567b157151"><br cl=
ass=3D"gmail_msg"><div class=3D"gmail_msg">This is a graph i get with my cu=
rrent intake of sun and my setup, consisting of thermo sensors on in- and o=
utgoing water pipes, as well as a water meter, emitting S0 impulses, indica=
ting that 10l of fluid were pumped.&nbsp;</div><div class=3D"gmail_msg">My =
Issue is with dealing with the impulses in a sensible way. The interval of =
these impulses varies, depending on the sun intake.&nbsp;</div><br class=3D=
"gmail_msg"><div class=3D"gmail_msg">currently my CDEF for the solar power =
is</div><div class=3D"gmail_msg">d,c,-,a,*,10,*,4.190,*<br class=3D"gmail_m=
sg"></div><div class=3D"gmail_msg">where c and d are my temperatures, and a=
 is my counter, indicating 10 liters. (4.190 is the specific heat constant =
of water.)</div><br class=3D"gmail_msg"><div class=3D"gmail_msg">Now what i=
s calculated by that CDEF is not really the solar power, its the momentary =
value, only, calculated for the duration of the impulse, which is the width=
 of my sampling rate (which is 10sec). it would have been more accurate to =
take the time between the impulses and calculate the incoming energy during=
 that period, divided by the duration of that time and graph that for the p=
revious (or following) interval.&nbsp;</div><br class=3D"gmail_msg"><div cl=
ass=3D"gmail_msg">How can I do that?&nbsp;</div></div>
<br class=3D"gmail_msg"></blockquote></div></div></div><div class=3D"gmail_=
msg"><div style=3D"font-family: arial,helvetica,sans-serif; font-size: 12pt=
; color: #000000;" class=3D"gmail_msg" data-mce-style=3D"font-family: arial=
,helvetica,sans-serif; font-size: 12pt; color: #000000;"><div class=3D"gmai=
l_msg"><blockquote style=3D"border-left: 2px solid #1010ff; margin-left: 5p=
x; padding-left: 5px; color: #000; font-weight: normal; font-style: normal;=
 text-decoration: none; font-family: Helvetica,Arial,sans-serif; font-size:=
 12pt;" class=3D"gmail_msg" data-mce-style=3D"border-left: 2px solid #1010f=
f; margin-left: 5px; padding-left: 5px; color: #000; font-weight: normal; f=
ont-style: normal; text-decoration: none; font-family: Helvetica,Arial,sans=
-serif; font-size: 12pt;">_______________________________________________<b=
r class=3D"gmail_msg">rrd-users mailing list<br class=3D"gmail_msg"><a href=
=3D"mailto:[email protected]" class=3D"gmail_msg" target=3D"_blank=
">[email protected]</a><br class=3D"gmail_msg"><a href=3D"https://=
lists.oetiker.ch/cgi-bin/listinfo/rrd-users" class=3D"gmail_msg" target=3D"=
_blank">https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users</a><br class=3D=
"gmail_msg"></blockquote></div></div></div><div class=3D"gmail_msg"><div st=
yle=3D"font-family: arial,helvetica,sans-serif; font-size: 12pt; color: #00=
0000;" class=3D"gmail_msg" data-mce-style=3D"font-family: arial,helvetica,s=
ans-serif; font-size: 12pt; color: #000000;"><br class=3D"gmail_msg"><div c=
lass=3D"gmail_msg">-- <br class=3D"gmail_msg"></div><div class=3D"gmail_msg=
">Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland<br=
 class=3D"gmail_msg"><a href=3D"http://www.oetiker.ch" class=3D"gmail_msg" =
target=3D"_blank">www.oetiker.ch</a> <a href=3D"mailto:[email protected]" cla=
ss=3D"gmail_msg" target=3D"_blank">[email protected]</a> <a href=3D"tel:+41%2=
062%20775%2099%2002" class=3D"gmail_msg" target=3D"_blank">+41 62 775 9902<=
/a></div></div></div></blockquote></div><br></blockquote></div><br><div dat=
a-marker=3D"__SIG_POST__">-- <br></div><div>Tobi Oetiker, OETIKER+PARTNER A=
G, Aarweg 15 CH-4600 Olten, Switzerland<br>www.oetiker.ch [email protected] +=
41 62 775 9902</div></div></body></html>
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