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Date: 16 Oct 2006 18:28:30
From: cpl593h
Subject: Fuji PXR input measuring range
My Fuji PXR4 is currently set to measure 32 F - 752 F. I was trying to
use a different program to interface my PID with my computer, and the
program automatically forced the measuring range from 0 F - 500 F.

I would like to know about the PXR's input measuring range (settings
P-SL and P-SU). When the measuring range is altered, it seems like the
thermocouple is offset slightly. Additionally, the original setpoint
values for a program are adjusted. I'm confused about what the PID is
actually doing internally when the measuring range is changed.

Is it preferrable to have a 0-500F range set, or is there really no
benefit? I assume that I would have to autotune to use a new range
setting.





 
Date: 27 Oct 2006 02:25:46
From: RoughJaw
Subject: Re: Fuji PXR input measuring range
Hey daveb,

Google had the audacity to remove your other Miss Penny post. In the
interest of allowing posterity to view you in your rightful place, it's
important that all of your posts remain intact. Don't you agree? Here
then, in its entirety, is another if your posts that went missing:

Path: postnews.google.com!m7g2000cwm.googlegroups.com!not-for-mail
Message-ID: <1161078524.653259.160030@m7g2000cwm.googlegroups.com >
From: "Miss Penny" <pennypey@yahoo.com >
Newsgroups: alt.coffee
Subject: Re: Fuji PXR input measuring range
Date: 17 Oct 2006 02:48:44 -0700
References: <1161048510.498904.203600@m7g2000cwm.googlegroups.com >
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No benefit.

Dave
128


cpl593h wrote:
> My Fuji PXR4 is currently set to measure 32 F - 752 F. I was trying to
> use a different program to interface my PID with my computer, and the
> program automatically forced the measuring range from 0 F - 500 F.
>
> I would like to know about the PXR's input measuring range (settings
> P-SL and P-SU). When the measuring range is altered, it seems like the
> thermocouple is offset slightly. Additionally, the original setpoint
> values for a program are adjusted. I'm confused about what the PID is
> actually doing internally when the measuring range is changed.
>
> Is it preferrable to have a 0-500F range set, or is there really no
> benefit? I assume that I would have to autotune to use a new range
> setting.

--
Posted via a free Usenet account from http://www.teranews.com



 
Date: 17 Oct 2006 12:11:38
From: cpl593h
Subject: Re: Fuji PXR input measuring range
Thank you everyone for the responses, and thank you Eric for e-mailing
me.

I forgot to mention that the PXR4 is controlling my FAB roaster. That
doesn't make so much of a difference as far as the info goes.



 
Date: 17 Oct 2006 11:44:56
From: gscace
Subject: Re: Fuji PXR input measuring range
This is correct. You get much better adjustability of proportional
band and other parameters that are given as a fraction of the operating
range if you set the range to a small er, useful window. I use 50
degrees F to 250 F for double boiler machines.

I forget what you said the controller was going into. I posted some
stuff on tuning PID controllers for espresso machines a while ago.
It's valid for the Fuji controller in systems where the water volume is
much greater than the heater volume (not the Silvia). It's not
apparently correct for controllers using traditional Nichols Ziegler
tuning.

-greg




Eric Svendson wrote:
> Not being intimately familar with PXR4 but I am getting familar with PXR3,
> P-SL and P-SU should/could be set to the range of interest.
>
> The proportional band (P) is set as a percentage of full scale and this
> scale depends on the input range. The default from Fuji is 32F (P-SL) to
> 1000F (P-SU). If your range were changed (by whatever means), I'm pretty
> sure that the band would automatically change. The percentage stays the
> same but since the range has changed, the numerical value of the band has
> changed. Your range changed from 720F to 500F and this is enough to trigger
> an overshoot depending upon your original value of P.
>
> Personally I would set P-SL and P-SU to 50F and 350F, respectively and
> autotune at 10% below my chosen Sv. Then start playing if you are not
> satisfied with the response. Even though I say this, I don't believe it
> matters what P-SL and P-SU are as long as you remember that its the
> numerical value of the band you are after and also that the controller will
> show an error if it measures any temp outside of your set band. Of course,
> setting P-SL and P-SU as I originally said might have other benefits that I
> am, at least for now, unaware of.
>
> The Fuji PXZ manual has some excellent explanations:
>
> http://www.ttiglobal.com/ProductFiles/4710/pxz_manual.pdf
>
> Eric S.
>
>
> "cpl593h" <CPL593H@gmail.com> wrote in message
> news:1161048510.498904.203600@m7g2000cwm.googlegroups.com...
> > My Fuji PXR4 is currently set to measure 32 F - 752 F. I was trying to
> > use a different program to interface my PID with my computer, and the
> > program automatically forced the measuring range from 0 F - 500 F.
> >
> > I would like to know about the PXR's input measuring range (settings
> > P-SL and P-SU). When the measuring range is altered, it seems like the
> > thermocouple is offset slightly. Additionally, the original setpoint
> > values for a program are adjusted. I'm confused about what the PID is
> > actually doing internally when the measuring range is changed.
> >
> > Is it preferrable to have a 0-500F range set, or is there really no
> > benefit? I assume that I would have to autotune to use a new range
> > setting.
> >



 
Date: 17 Oct 2006 16:30:46
From: RoughJaw
Subject: Re: Fuji PXR input measuring range
On Tue, 17 Oct 2006 02:48:44 -0700, Miss Penny wrote:

> No benefit.
>
> Dave
> 128

Oooops...

--
Posted via a free Usenet account from http://www.teranews.com



 
Date: 17 Oct 2006 02:48:44
From: Miss Penny
Subject: Re: Fuji PXR input measuring range
No benefit.

Dave
128


cpl593h wrote:
> My Fuji PXR4 is currently set to measure 32 F - 752 F. I was trying to
> use a different program to interface my PID with my computer, and the
> program automatically forced the measuring range from 0 F - 500 F.
>
> I would like to know about the PXR's input measuring range (settings
> P-SL and P-SU). When the measuring range is altered, it seems like the
> thermocouple is offset slightly. Additionally, the original setpoint
> values for a program are adjusted. I'm confused about what the PID is
> actually doing internally when the measuring range is changed.
>
> Is it preferrable to have a 0-500F range set, or is there really no
> benefit? I assume that I would have to autotune to use a new range
> setting.



  
Date: 20 Oct 2006 19:55:21
From: RobvL
Subject: Re: Fuji PXR input measuring range
You posted from the wrong ID Dave.


"Miss Penny" <pennypey@yahoo.com > wrote in message
news:1161078524.653259.160030@m7g2000cwm.googlegroups.com...
> No benefit.
>
> Dave
> 128
>
>
> cpl593h wrote:
> > My Fuji PXR4 is currently set to measure 32 F - 752 F. I was trying to
> > use a different program to interface my PID with my computer, and the
> > program automatically forced the measuring range from 0 F - 500 F.
> >
> > I would like to know about the PXR's input measuring range (settings
> > P-SL and P-SU). When the measuring range is altered, it seems like the
> > thermocouple is offset slightly. Additionally, the original setpoint
> > values for a program are adjusted. I'm confused about what the PID is
> > actually doing internally when the measuring range is changed.
> >
> > Is it preferrable to have a 0-500F range set, or is there really no
> > benefit? I assume that I would have to autotune to use a new range
> > setting.
>




 
Date: 17 Oct 2006 01:19:40
From: Eric Svendson
Subject: Re: Fuji PXR input measuring range
Not being intimately familar with PXR4 but I am getting familar with PXR3,
P-SL and P-SU should/could be set to the range of interest.

The proportional band (P) is set as a percentage of full scale and this
scale depends on the input range. The default from Fuji is 32F (P-SL) to
1000F (P-SU). If your range were changed (by whatever means), I'm pretty
sure that the band would automatically change. The percentage stays the
same but since the range has changed, the numerical value of the band has
changed. Your range changed from 720F to 500F and this is enough to trigger
an overshoot depending upon your original value of P.

Personally I would set P-SL and P-SU to 50F and 350F, respectively and
autotune at 10% below my chosen Sv. Then start playing if you are not
satisfied with the response. Even though I say this, I don't believe it
matters what P-SL and P-SU are as long as you remember that its the
numerical value of the band you are after and also that the controller will
show an error if it measures any temp outside of your set band. Of course,
setting P-SL and P-SU as I originally said might have other benefits that I
am, at least for now, unaware of.

The Fuji PXZ manual has some excellent explanations:

http://www.ttiglobal.com/ProductFiles/4710/pxz_manual.pdf

Eric S.


"cpl593h" <CPL593H@gmail.com > wrote in message
news:1161048510.498904.203600@m7g2000cwm.googlegroups.com...
> My Fuji PXR4 is currently set to measure 32 F - 752 F. I was trying to
> use a different program to interface my PID with my computer, and the
> program automatically forced the measuring range from 0 F - 500 F.
>
> I would like to know about the PXR's input measuring range (settings
> P-SL and P-SU). When the measuring range is altered, it seems like the
> thermocouple is offset slightly. Additionally, the original setpoint
> values for a program are adjusted. I'm confused about what the PID is
> actually doing internally when the measuring range is changed.
>
> Is it preferrable to have a 0-500F range set, or is there really no
> benefit? I assume that I would have to autotune to use a new range
> setting.
>




 
Date: 16 Oct 2006 23:04:20
From: Dan Bollinger
Subject: Re: Fuji PXR input measuring range
> My Fuji PXR4 is currently set to measure 32 F - 752 F. I was trying to
> use a different program to interface my PID with my computer, and the
> program automatically forced the measuring range from 0 F - 500 F.

I don't recall that setting on mine. I do know that some PIDs will self-adjust
the hi-lo range based on your selection of thermocouple. Dunno if the Fuji does
or not. Dan