[TRNSYS-users] question related to type2

[Angel Carrera]

Egun on Carol,

I think there a two basic reasons for this:

1-The controller gets stuck due to a lack of stability of your model.
Parameter 1 sets the number of oscillations that the controller can do in a
single time step; if the controller changes of state while trnsys is
iterating within a time step, it will never do it (change) more times than
the value you have set in parameter 1, so it gets fixed when the number of
changes reaches that value. I can't explain it better than it is done in
the user help (at least in english), so I recommend you to carefully read
the introduction in the controllers section of the mathematical reference
on the trnsys help as well as type 2b section. To solve this, usually the
best you can do is reduce you time step until you have a coherent behaviour
of the controller.

2-The monitoring temperature is governing the controller. If the Input
Control Functio (inputs tab of the proforma) exceeds the value of the
parameter 2, then the controller output is set to 0.

I imagine that the first possibility is the one explaining that behaviour;
reducing the time step is probably a good help for your model, good luck

Angel


2014/1/24 Pascual Ortiz, Carol <carol.pascual at tecnalia.com>

>  Hi TRNSYS user,
>
>
>
> In my last simulation I use type 2 on/off differential controllers and I
> do not know why sometimes it works ok and others doesn´t.
>
>
>
> For example Time step                temperature
>                       control  signal
>
>                                 4016,65
> 25                                                  0
>
>                                 4016,70
> 25                                                  1
>
>                                 4016,75
> 25                                                  0
>
>
>
> Do you know what I am doing wrong? Does this ever happen to you?
>
> Thank you in advance,
>
> Best regards,
>
>
>
> *Carol Pascual*
>
> Energía Térmica/Thermal Energy
>
>
>
> *División de Energía y Medio Ambiente/*
>
> *Energy and Environment Division*
>
>
>
> *TECNALIA*
>
> Área Anardi,5
>
> Laida Bidea, Edificio 204
>
> E-20730 Azpeitia - Gipuzkoa (Spain)
>
> T 902 760 000*
>
> M 667119581
>
> T +34 946 430 850 (International calls)
>
> carol.pascual at tecnalia.com
>
> www.tecnalia.com
>
>
>
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>
>


-- 
*Àngel Carrera*


*Consultor SeniorÀrea tècnica*

Sistemes Avançats d'Energia Solar Tèrmica SCCL
C/ Roger de Llúria, 29 3r 2a 08009 Barcelona
Mòbil: (+34) 663 27 66 80
Tel: (+34) 93 342 47 55
Fax: (+34) 93 342 47 56

angel.carrera at aiguasol.coop
http://www.aiguasol.coop
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