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rcrabb22
Joined: 23 Dec 2010
Posts: 462
Location: Illinois
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 Link Posted: Sun Dec 03, 2017 5:17 pm Post subject: HLT PID +1 degree over set point |
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My HLT PID maintains the water temperature 1F above the set point. It does it consistently over the entire time I am using the HLT. Any ideas why?
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kal
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Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
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rcrabb22
Joined: 23 Dec 2010
Posts: 462
Location: Illinois
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| Link Posted: Tue Dec 05, 2017 11:46 am Post subject: |
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I did the auto-tune process yesterday and now the HLT is set to 152 and the PID is holding the HLT at 154 energizing the element when the HLT temperature drops to 153. I verified the temperature reported by the HLT matches with a Thermapen. I thought maybe the SSR was "leaking" but that would not explain the PID energizing the heating element at 153 when the set value was 152.
I am going to swap the MLT PID for the HLT PID and go through the auto-tune again.
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kal
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Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
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rcrabb22
Joined: 23 Dec 2010
Posts: 462
Location: Illinois
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| Link Posted: Tue Dec 05, 2017 11:07 pm Post subject: |
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| kal wrote: | Strange.
You built this control panel back in 2012 if I'm not mistaken, correct? Is this a new issue that just developed? Were any of the PID settings changed that may have caused it behave oddly?
Just to be sure, you may want to go through the PID settings in the manual and reset everything to the default settings and then follow our control panel setup instructions and try an auto-tune again.
Kal |
Yes I built in 2012 and the issue appeared 2 brews ago. As for the settings I thought about that too. Before I do any PID swapping I was going to verify the settings. Maybe I changed one accidentally when setting alarms or tweaking temperature probe offset. I will try your suggestion regarding the settings and run the auto-tune again.
Thanks
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kal
Forum Administrator
Joined: 12 Dec 2010
Posts: 11121
Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
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Ozarks Mountain Brew
Joined: 22 May 2013
Posts: 737
Location: The Ozark Mountains of Missouri
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| Link Posted: Wed Dec 06, 2017 3:28 am Post subject: |
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its possible you need to give the temp probe end a good abrasive cleaning
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rcrabb22
Joined: 23 Dec 2010
Posts: 462
Location: Illinois
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| Link Posted: Wed Dec 06, 2017 4:06 pm Post subject: |
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An update FWIW
I went through my PID settings and noticed
I was set to 1412
P was set way out at 2918
D was set to 186
I am 99% sure I never messed with these settings and let auto-tune modify them although I never checked them.
One thing I also noticed doing the last 2 auto-tune attempts: I started the auto-tune at 140F and the set value was 151. The HLT temperature was raised to 154 and the temperature never dropped from that reading the entire time the auto-tune "AT" was alternating with SV display that I noticed. I didn't watch the entire time but looked at it often while reading back issues of BYO. The auto-tune took about 25 minutes the first time and over an hour the 2nd time.
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rcrabb22
Joined: 23 Dec 2010
Posts: 462
Location: Illinois
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| Link Posted: Thu Dec 07, 2017 6:36 pm Post subject: |
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Last Update
The PID is acting strangely now. I went through an auto-tune 1 last time after setting I,P and D to the default values. It held the HLT temperature at 152 with a set value of 151. I verified the temperature once again with my Thermapen.
BUT it also changed the t value from 2 to 30. I changed it back to 2 and the displayed temperature measurement value changed to 760. I changed it back to 30 and the temp displayed as 152 again! I verified the Sn setting was still 21 (Rt100 probe) and the COOL setting was 10 (Fahrenheit and heating mode).
Time to replace the PID.
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kal
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Joined: 12 Dec 2010
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Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
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rcrabb22
Joined: 23 Dec 2010
Posts: 462
Location: Illinois
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| Link Posted: Thu Dec 07, 2017 9:19 pm Post subject: |
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| kal wrote: | Before replacing the PID I would reset all to default values and try it. Values shouldn’t change by themselves as that’s not hardware that breaks.
Kal |
I agree. I hope I didn't find a bug in the firmware or it was corrupted in some way.
I did reset all the values per the manual and ran my HLT up to the set temp of 151. It brought it up to 154 and held it there. I verified with a Themapen the reported temperature of the probe was 154.5 F versus the Thermapen reading of 154. I had the Pb value set to -.5 before but set Pb to zero for this test run.
After that I shut down the HLT element and let the HLT drop to 139F. I then enabled the HLT element again and started the auto-tune. When it finished that is when I discovered the t value was set to 30. I cannot find any mention that the t value is modified by the auto-tune process. I do not see a correlation between the t value setting and the temperature display in the manual either. I can reproduce the temperature display behavior changing the t value at will.
Now that I retired I have plenty of time to run these experiments. 
I really do not know what is going on. I am going to place a call to Auber Instruments and seek their guidance.
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kal
Forum Administrator
Joined: 12 Dec 2010
Posts: 11121
Location: Ottawa, Canada
Drinking: Pub Ale, Electric Creamsicle, Mild, Pliny the Younger, Belgian Dark Strong, Weizen, Russian Imperial Stout, Black Butte Porter
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chastuck
Joined: 06 Oct 2013
Posts: 193
Location: Beckenham, Kent, UK
Drinking: Bitter
Working on: IPA
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| Link Posted: Thu Dec 07, 2017 9:47 pm Post subject: |
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Whenever I have done an auto-tune with the SYL 2352 it has always changed the t setting away from 2. Some example settings in my case have been 14 and 56.
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rcrabb22
Joined: 23 Dec 2010
Posts: 462
Location: Illinois
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| Link Posted: Fri Dec 08, 2017 2:13 pm Post subject: |
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| chastuck wrote: | | Whenever I have done an auto-tune with the SYL 2352 it has always changed the t setting away from 2. Some example settings in my case have been 14 and 56. |
That is reassuring. It might be the PID has undocumented behavior. Another case of "Need to Know?"
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