[TRNSYS-users] Type2b

[David BRADLEY]

Ciaran,
   It may be that the controller arrived at its oscillation limit during 
that time step. The parameter NSTK limits how many times the controller 
can change states within the iterations of a single time step.
Best,
  David


On 10/19/2012 11:14, Flynn Ciaran wrote:
>
> Hello,
>
> After having read the documentation and online help, I am still having 
> trouble with the type 2b and I was wondering if you could please help 
> me out. My problem is the following:
>
> I used the example file SDHW, where the Type2b is connected as follows:
>
> Upper limit TH= solar collector output temperature
>
> Lower limit TL= tank to heat source temperature
>
> Monitoring temperature TIN= tank to load temperature
>
> Upper deadband ?TH= 15 degrees
>
> Lower deadband ?TL= 0 degrees
>
> Then I went through the documented equations (Eq. 4.1-1 to Eq.4.1-4). 
> However in the simulation results, when I take a look at time steps 
> 4064.25 to 4065 (as an example), I find the following:
>
> Time step
>
> 	
>
> 4064.25
>
> 	
>
> 4064.5
>
> 	
>
> *4064.75*
>
> 	
>
> 4065
>
> (TH-TL)
>
> 	
>
> -1.373
>
> 	
>
> 7.008
>
> 	
>
> *1.618*
>
> 	
>
> 2.304
>
> ?i
>
> 	
>
> 0
>
> 	
>
> 0
>
> 	
>
> *0*
>
> 	
>
> 1
>
> ?o
>
> 	
>
> 0
>
> 	
>
> 0
>
> 	
>
> *1*
>
> 	
>
> 1
>
> From what I see, time step *4064.75* does not agree with *Eq. 4.1-3 
> *since (TH-TL) is still below the upper deadband even though the 
> controller is turned on (it should remain off until (TH-TL) is greater 
> than or equal to the upper deadband). Maybe I am misreading the 
> input/output controller values?**
>
> Any help would be greatly appreciated.
>
> Thanks,
> Ciaran
>
> **
>
>
>
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> TRNSYS-users at cae.wisc.edu
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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com

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