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Date: 30 Dec 2006 11:37:05
From:
Subject: Strange update on PID to puck temp spread
OK. I'm confused (moreso than usual)
RE: the previous topic about Silvia's PID displaying 205F with a
measured temp at the puck of 200F.
I removed the top cover and put the bead of the termocouple next to the
PID thermocouple and the readings were withing a few tenths.
Against the prevailing wisdom here, I couldn't help myself and
autotuned the Love 32B. Now with the pid at 221F the water on the puck
is 203F??????????????????

This seems to be much closer to the variation that most people here
reported,

I hate it when something is improved and I don't know why.
My understanding (extremely limited) of autotuning doesn't seem to
explain this.
Stan "Hot and confused" S





 
Date: 30 Dec 2006 12:27:53
From:
Subject: Re: Strange update on PID to puck temp spread

Randy G. wrote:
> stan.shire@gmail.com wrote:
>
> >OK. I'm confused (moreso than usual)
> >RE: the previous topic about Silvia's PID displaying 205F with a
> >measured temp at the puck of 200F.
> >I removed the top cover and put the bead of the termocouple next to the
> >PID thermocouple and the readings were withing a few tenths.
> >Against the prevailing wisdom here, I couldn't help myself and
> >autotuned the Love 32B. Now with the pid at 221F the water on the puck
> >is 203F??????????????????
> >
> >This seems to be much closer to the variation that most people here
> >reported,
> >
> >I hate it when something is improved and I don't know why.
> >My understanding (extremely limited) of autotuning doesn't seem to
> >explain this.
> >Stan "Hot and confused" S
>
> I am sure Andy, Greg, or someone else more knowledgeable than I am in
> this field might be able to comment.. My opinion is that thermal
> energy is thermal energy, and how you arrive at the stable thermal
> point might be affected by auto tuning, but auto tuning should have no
> effect on the indicated boiler temperature in relation to the actual
> brew temp. If the probe type was changed in the PID's programming,
> that would affect it, or maybe if you disturbed the probe's wire and
> in its old location it was being affected by some electronic or
> electromagnetic source....
>
> Were you wearing your aluminum foil hat before? ;-)
>
> Randy "...and then they probed me" G.
> http://www.EspressoMyEspresso.com
No, but my windows are still covered in foil.
S



 
Date: 30 Dec 2006 12:11:56
From: Randy G.
Subject: Re: Strange update on PID to puck temp spread
stan.shire@gmail.com wrote:

>OK. I'm confused (moreso than usual)
>RE: the previous topic about Silvia's PID displaying 205F with a
>measured temp at the puck of 200F.
>I removed the top cover and put the bead of the termocouple next to the
>PID thermocouple and the readings were withing a few tenths.
>Against the prevailing wisdom here, I couldn't help myself and
>autotuned the Love 32B. Now with the pid at 221F the water on the puck
>is 203F??????????????????
>
>This seems to be much closer to the variation that most people here
>reported,
>
>I hate it when something is improved and I don't know why.
>My understanding (extremely limited) of autotuning doesn't seem to
>explain this.
>Stan "Hot and confused" S

I am sure Andy, Greg, or someone else more knowledgeable than I am in
this field might be able to comment.. My opinion is that thermal
energy is thermal energy, and how you arrive at the stable thermal
point might be affected by auto tuning, but auto tuning should have no
effect on the indicated boiler temperature in relation to the actual
brew temp. If the probe type was changed in the PID's programming,
that would affect it, or maybe if you disturbed the probe's wire and
in its old location it was being affected by some electronic or
electromagnetic source....

Were you wearing your aluminum foil hat before? ;-)

Randy "...and then they probed me" G.
http://www.EspressoMyEspresso.com