[TRNSYS-users] PID controller in TRNSYS developer

David BRADLEY d.bradley at tess-inc.com
Mon Nov 14 10:17:49 PST 2011


Wang,
   You should already have the source code for the PID controller in 
..\TrnsysXX\SourceCode\Types\. I would also recommend reading the Type23 
section of the 04-MathematicalDescription manual.

   PID controllers can operate in one of two ways: they can generate a 
greater signal value if the sampled input value is below the set point 
or they can generate a greater signal value if the sampled input is 
above the current set point. Imagine a heating application with a PID 
controller. As the zone temperature falls, you want the PID to give you 
a bigger and bigger signal. Now imagine a cooling application. As the 
zone temperature rises, you want the PID to give you a bigger and bigger 
signal. You may have to add an equation after the PID to invert its 
control signal if it is acting the opposite of the way that you want.

David

On 11/14/2011 04:28, wangyang wrote:
> Dear all,
>     I have a question about PID controller in TRNSYS for its developer.
>     Which expert knows PID controller in TRNSYS developer? Or Which 
> expert could pass me the source code of PID controller or its internal 
> algorithm etc.? I guess PID controller in TRNSYS is based on empirical 
> equation or iterative algorithm. Since there is *very weird* 
> simulation results i.e. I set the set point CO2 concentration 1000 ppm 
> as PID controller's set point; its control signal links to Opening 
> Factor (OF) of windows; indoor CO2 concentration links to PID's 
> controlled variable. However, when indoor CO2 concentration is less 
> than set point 1000 ppm, PID begins to activate OF i.e. windows are 
> open. But based on PID principle, as we know, if CO2 concentration is 
> not getting to set point 1000 ppm, at this time windows are open will 
> result in *the ERROR* (between the set point and actual indoor CO2 
> concentration)*increasing. *So I'm puzzled! Please PID controller in 
> TRNSYS developer or other experts explain this weird phenomenon!
> Many thanks in advance!
>    br
>    wang
>
>
> 2011/11/12 <trnsys-users-request at cae.wisc.edu 
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>     Today's Topics:
>
>       1. Re: (no subject) (David BRADLEY)
>       2. Re: TRNSYS3D Shading on Walls? (David BRADLEY)
>       3. Re: how to identify a wall that is adjacent two walls
>          (David BRADLEY)
>       4. Error in reading type 51 external performance File
>          (Walif M'kacher)
>
>
>     ---------- ????? ----------
>     From: David BRADLEY <d.bradley at tess-inc.com
>     <mailto:d.bradley at tess-inc.com>>
>     To: Erik Boschek <erikboschek at yahoo.com
>     <mailto:erikboschek at yahoo.com>>
>     Date: Fri, 11 Nov 2011 12:01:47 -0600
>     Subject: Re: [TRNSYS-users] (no subject)
>     Erik,
>      You are right on with all three of your points. For reference, we
>     discontinued use of Type109 in Trnsys17 in favor of option 2
>     (Type15), which is correct from an energy perspective even though
>     it isn't a smooth curve. In gernal think that a control strategy
>     that relies only on the instantaneous DNI as its input might run
>     into trouble not only in simulation but also in the real world;
>     clouds pass in front of the sun rapidly sometimes. While I won't
>     pretend that the "spiky" profile that Type15 generates is totally
>     realistic, I think it is a fairly accurate representation of DNI.
>     Bear in mind that Type15 is trying to reconstruct a minute by
>     minute radiation profile based only on 1 number and to do so
>     correctly for all possible climate types. You might consider a
>     control strategy that uses the output of Type15 but put through a
>     running-average component so that your control decisions are based
>     on a somewhat more stable (smoother) profile.
>     Best,
>      David
>
>
>     On 11/11/2011 00:32, Erik Boschek wrote:
>>
>>     Dear TRNSYS users,
>>
>>     I have a simple question regarding weather reading and
>>     interpolating direct normal radiation (DNI) values for time steps
>>     less than an hour.
>>
>>     As long as I have been using TRNSYS (using TRNSYS 16.1) I have
>>     understood this can be done in a few ways as follows, including
>>     the consequence for an example TM2 file (see attached screen shot
>>     for clarification):
>>
>>     1.) Do not interpolate, using Type 15 with output DNR (not
>>     interpolated): you end up with a "steppy" profile
>>     2.) Using Type 15, but with 2-axis tracking and the output "Beam
>>     radiation for surface": you get a discontinuous "spikey" profile,
>>     but the integration of energy across the hour is respected
>>     3.) Same as 2, but using Type109-TMY2: You get a smooth profile,
>>     but often there appear inexplicable spikes at the beginning or
>>     end of the day. The one in the plot obviously is an extreme case.
>>
>>     For reference: I just used the Daggett profile
>>     "US-CA-Daggett-23161.tm2" which came with TRNSYS, but the
>>     behavior is not specific to this file.
>>
>>     Generally, I have been using 2, but it can cause problems if
>>     there is, for example, some triggering function based on DNI and
>>     the DNI hovers around the threshold. Is there another option for
>>     getting a smoother profile or is it best just to not interpolate?
>>     Any opinions? Feel free to point me to an earlier post on this
>>     topic in case I missed it.
>>
>>     Thanks,
>>
>>     Erik Boschek
>>
>>
>>
>>
>>
>>
>>
>>
>>     _______________________________________________
>>     TRNSYS-users mailing list
>>     TRNSYS-users at cae.wisc.edu  <mailto:TRNSYS-users at cae.wisc.edu>
>>     https://mailman.cae.wisc.edu/listinfo/trnsys-users
>
>     -- 
>     ***************************
>     David BRADLEY
>     Principal
>     Thermal Energy Systems Specialists, LLC
>     22 North Carroll Street - suite 370
>     Madison, WI  53703 USA
>
>     P:+1.608.274.2577  <tel:%2B1.608.274.2577>
>     F:+1.608.278.1475  <tel:%2B1.608.278.1475>
>     d.bradley at tess-inc.com  <mailto:d.bradley at tess-inc.com>
>
>     http://www.tess-inc.com  <http://www.tess-inc.com/>
>     http://www.trnsys.com  <http://www.trnsys.com/>
>
>
>
>     ---------- ????? ----------
>     From: David BRADLEY <d.bradley at tess-inc.com
>     <mailto:d.bradley at tess-inc.com>>
>     To: Marion Hiller <hiller at transsolar.com
>     <mailto:hiller at transsolar.com>>
>     Date: Fri, 11 Nov 2011 12:03:16 -0600
>     Subject: Re: [TRNSYS-users] TRNSYS3D Shading on Walls?
>     TRNSYS-users,
>      My apologies; my reply to Graham was incorrect; as Marion says,
>     only the windows are affected.
>     Kind regards,
>      David
>
>
>     On 11/11/2011 01:33, Marion Hiller wrote:
>
>         Graham,
>
>         the shading defined in Trnsys3D effects only windows.
>
>         Marion
>
>         Dipl.-Ing. Marion Hiller
>         TRANSSOLAR: KlimaEngineering - Technologien für
>         energieeffizientes Bauen
>         und Nutzerkomfort in Gebäude
>         Munich - New York - Stuttgart + 49.711.67976.0
>         <tel:%2B%2049.711.67976.0>
>
>         Transsolar Energietechnik GmbH, Curiestrasse 2, 70563 Stuttgart
>         Amtsgericht Stuttgart - HRB 23347, Steuernummer 99073/00911,
>         USt-IdNr.:
>         DE152272639
>         Geschäftsführer: Dipl.Ing. Matthias Schuler, Dipl.Ing. Thomas
>         Auer,
>         Dipl.Phys. Stefan Holst, Prof. Dipl.-Ing. Bleicher
>
>
>
>         -----Ursprüngliche Nachricht-----
>         Von: Graham Linn [mailto:grahamjlinn at gmail.com
>         <mailto:grahamjlinn at gmail.com>]
>         Gesendet: Donnerstag, 10. November 2011 21:49
>         An: trnsys-users at cae.wisc.edu <mailto:trnsys-users at cae.wisc.edu>
>         Betreff: [TRNSYS-users] TRNSYS3D Shading on Walls?
>
>         Hello TRNSYS users,
>
>         I have a question about shading in TRNSYS3D. Does a shading object
>         affect how much insolation hits the entire building or just the
>         windows on the building?
>
>         Thank you!
>         Graham
>         _______________________________________________
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>
>
>
>         _______________________________________________
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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 <tel:%2B1.608.274.2577>
>     F:+1.608.278.1475 <tel:%2B1.608.278.1475>
>     d.bradley at tess-inc.com <mailto:d.bradley at tess-inc.com>
>
>     http://www.tess-inc.com <http://www.tess-inc.com/>
>     http://www.trnsys.com <http://www.trnsys.com/>
>
>
>
>
>     ---------- ????? ----------
>     From: David BRADLEY <d.bradley at tess-inc.com
>     <mailto:d.bradley at tess-inc.com>>
>     To: Nidal Abdalla <nidalabdalla at yahoo.com
>     <mailto:nidalabdalla at yahoo.com>>
>     Date: Fri, 11 Nov 2011 12:29:48 -0600
>     Subject: Re: [TRNSYS-users] how to identify a wall that is
>     adjacent two walls
>     Nidal,
>       You have to be a little careful here. If you have a wall in zone
>     1, half of which is adjacent to zone 2 and half of which is
>     adjacent to zone 3, you actually need to draw the wall as two
>     walls in zone 1. Trnsys3D requires the user to be quite vigilant
>     about manually setting adjacencies. You need to draw the ADJACENT
>     wall in both zones and you need to open the object window for each
>     of them, set the construction to ADJ_WALL, set the "outside
>     boundary condition" to "Zone" and then manually select the zone to
>     which it is adjacent in the "outside boundary object" field.
>
>       If you have been very careful about drawing your ADJACENT walls
>     so that they have exactly the same verticies in both zones to
>     which they belong, you can then select the menu item:  Plugins:
>     Trnsys3d: Surface Matching and click the "match in entire model"
>     button.
>
>     Kind regards,
>      David
>
>
>     On 11/11/2011 08:32, Nidal Abdalla wrote:
>>     I drew a house using Trnsys3d that consists of: 3 bed rooms,
>>     living room, guest room and bath . The house was divided into 6
>>     zones. Wall_zone5, for example, is adjacent two walls for two
>>     different zones. I am wondering how to identify a wall (using
>>     Object Info) that is adjacent two or more walls of diff. zones.
>>     Best Regards
>>     Nidal Abdalla
>>
>>
>>     _______________________________________________
>>     TRNSYS-users mailing list
>>     TRNSYS-users at cae.wisc.edu  <mailto:TRNSYS-users at cae.wisc.edu>
>>     https://mailman.cae.wisc.edu/listinfo/trnsys-users
>
>     -- 
>     ***************************
>     David BRADLEY
>     Principal
>     Thermal Energy Systems Specialists, LLC
>     22 North Carroll Street - suite 370
>     Madison, WI  53703 USA
>
>     P:+1.608.274.2577  <tel:%2B1.608.274.2577>
>     F:+1.608.278.1475  <tel:%2B1.608.278.1475>
>     d.bradley at tess-inc.com  <mailto:d.bradley at tess-inc.com>
>
>     http://www.tess-inc.com  <http://www.tess-inc.com/>
>     http://www.trnsys.com  <http://www.trnsys.com/>
>
>
>
>     ---------- ????? ----------
>     From: "Walif M'kacher" <walif.mkacher at gmail.com
>     <mailto:walif.mkacher at gmail.com>>
>     To: trnsys-users at cae.wisc.edu <mailto:trnsys-users at cae.wisc.edu>
>     Date: Sat, 12 Nov 2011 15:13:05 +0100
>     Subject: [TRNSYS-users] Error in reading type 51 external
>     performance File
>
>     Dear TRNSys Users,
>
>     I have a problem with external file of type 51a (cooling tower
>     with an external performance File):
>
>
>     That the simulation with this type causes error and this can't
>     read this external file (.txt)
>
>
>
>     Would you please help me how to correct the file joined or send me
>     a truth format of this .txt file
>
>
>     Many thanks in advance
>
>     _Mkacher Walif_
>
>
>     _______________________________________________
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>
>
>
>
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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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