[TRNSYS-users] problem about the differential controller (Type2)

[Yin Hang]

Hi Matthias,
Thanks a lot.
You method solved this problem.
Regards,
Yin

-----Original Message-----
From: Kersken, Matthias [mailto:Matthias.Kersken at ibp.fraunhofer.de] 
Sent: Wednesday, September 16, 2009 2:36 AM
To: Yin Hang; Francois Badinier; trnsys-users at cae.wisc.edu
Subject: AW: [TRNSYS-users] problem about the differential controller
(Type2)

Hello Yin!

As far as I know this controller already switches when he would exceed his
deadband on the previous output-setting.
This is to prevent the controlled variable from exceeding the
upper-limit-value.
I suspect You have two options:
- Choose a bigger Daedband.
- Set in the "parameter"-card the "number of oscillation" to a non-odd value
like 4 or 6 (not 5). This should make Your controller less willing to switch
becaus if he's oscillating and is finding no solution he'll not change but
stay on the same value.

Ich hope I could help You!

With regards,
	Matthias Kersken


---
 
Dipl.-Ing. Matthias Kersken
Wissenschaftlicher Mitarbeiter / Abteilung Energiesysteme
Fraunhofer-Institut für Bauphysik 
Institutsteil Holzkirchen
Fraunhoferstraße 10
83626 Valley
eMail: Matthias.Kersken at ibp.fraunhofer.de
Telefon 08024 / 643-204
Telefax 08024 / 643-366
www.ibp.fraunhofer.de
Dipl.-Ing. Matthias Kersken
Research Associate / Department Energy Systems 
Fraunhofer Institute for Building Physics 
Branch Holzkirchen
Fraunhoferstraße 10
D-83626 Valley
eMail: Matthias.Kersken at ibp.fraunhofer.de
Phone +49 8024 / 643-204
Fax +49 8024 / 643-366
www.ibp.fraunhofer.de
 
 
 
 
 
 
 
 
 
 
 
 
 
---

-----Ursprüngliche Nachricht-----
Von: Yin Hang [mailto:yhang at purdue.edu] 
Gesendet: Dienstag, 15. September 2009 17:08
An: 'Francois Badinier'; trnsys-users at cae.wisc.edu
Betreff: Re: [TRNSYS-users] problem about the differential controller
(Type2)

Hello,
Thanks for your replying.
I have connected connect the output of the controller to its "input control
function" (input 4).
But if you look at the example in TRNSYS - "DHSW", you will also find this
fluctuation problem.(suddenly on and suddenly off, even still in the
deadband).
Thanks.
Yin

-----Original Message-----
From: Francois Badinier
[mailto:francois.badinier at icax.co.uk]
Sent: Tuesday, September 15, 2009 5:11 AM
To: 'Yin Hang'; trnsys-users at cae.wisc.edu
Subject: RE: [TRNSYS-users] problem about the differential controller
(Type2)

Yin,

Make sure you connect the output of the controller to its "input control
function" (input 4). You link the controller with itself basically. This has
to be done in order to get the hysteresis effect working (influence of the
previous state).
With that done, it should work properly.

Regards,

François Badinier
Development Engineer
ICAX Ltd
1 Hatfield House
Baltic Street West
London EC1Y OST
francois.badinier at icax.co.uk
www.icax.co.uk




-----Original Message-----
From: Yin Hang [mailto:yhang at purdue.edu]
Sent: 14 September 2009 19:47
To: trnsys-users at cae.wisc.edu
Subject: [TRNSYS-users] problem about the differential controller (Type2)

Hello,
I have a problem when I use differential controller type2.
For example, I want to control my solar collector loop pump by using one of
this controller.
My control logic is when the outlet temperature of my solar collector is
higher than the inlet temperature of my solar collector 4C, the pump will be
on; And when it is lower than the inlet temperature for 2C, the pump will be
off.
However, I found the output control signal is fluctuated, such as it
suddenly becomes off even the outlet temperature is 2C higher than the
outlet temperature; and next timestep, it suddenly on.
Could you help me to fix this problem? I figure it is really bad since it is
un-normal for my pump during true situation.
Thanks.



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