[TRNSYS-users] type 9 problem

[David Bradley]

Constanze,
   TRNSYS should accept any time step for the data file. You need to make 
sure that your data file time step is at least as big as your simulation 
times step. In other words you cannot run a simulation time step of 1 hour 
and a data reading time step of 5 minutes. The second issue may be that a 
time step of 1/12 results in an infinitely repeating decimal 
(0.08333333...) and when you enter 0.0833 for the fourth parameter of 
Type9, TRNSYS interprets this to mean 0.0833000. After a few time steps the 
simulation starts running into problems of the data file and the simulation 
time step not matching up. One solution is that you can change the fourth 
parameter from units of "hours" to units of "string" and define a variable 
called "DataStep." You then need to add an equation to your input file that 
defines DataStep = 1/12. In that way, the TRNSYS engine will have much more 
precision and there will not be as much mismatch between the simulation and 
data reading time steps. I should mention also that Stefan is correct that 
the safest simulation and data reading time steps have the form 1/(2^n) 
because those never result in repeating decimals.

   The second problem that you describe (Using 1 hr (to see if the type 
works) I get the error message that the system is not able to read the file 
correctly) must be specific to the data file and setup of Type9. If you 
would like to send me your *.tpf file and the data file, I can take a look 
at it for you.
Cheers,
  David


At 00:47 6/1/2006, Constanze.Bongs at csiro.au wrote:
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>
>Hi,
>
>
>
>I am new to using TRNSYS and have run across the following problem which I 
>could not resolve using the manual or the mailing list archives. It is 
>probably really easy but I would be very happy if someone could give me a 
>“helping hand”.
>
>
>
>I want TRNSYS to read data (temperatures and relative humidity) from an 
>excel file and use that data as input to a building model. The data in the 
>sheet is taken at time steps of  5 minutes. I tried using TYPE 9 to read 
>it.  However, when I try running the simulation (or Type 9 separately) I 
>get the following error messages:
>
>1.) The system does not seem to allow me to input data time steps of less 
>than 1 hour into parameter 4 (time interval of data) – although it should 
>if I am well informed. I tried to use hrs as unit and filled in 1/12 or 
>0,0833 but still the same problem occurred. If I set it back at 1 hr it 
>does not give me the error message any more, but that does not make sense 
>with the data I want to use.
>
>2.) Using 1 hr (to see if the type works) I get the error message that the 
>system is not able to read the file correctly. I inserted the path to the 
>file under external files (and under files in the window that opens as I 
>click on information). I checked the deck file and it gives me the right 
>path to the excel sheet. I also checked the excel sheet but can find no 
>error in the sheet. However, I cannot get TRNSYS to run the simulation 
>(type 9) and read the file.
>
>
>
>Well, hope someone can help.
>
>
>
>Cheers,
>
>
>
>Constanze
>
>
>
>
>
>-------------------------------------------------------------
>
>Constanze Bongs
>
>CSIRO Division of Energy Technology
>
><mailto:Constanze.Bongs at csiro.au>Constanze.Bongs at csiro.au
>
>Ph: 02 4960 6104
>
>fax: 02 4960 6111
>
>-------------------------------------------------------------
>
>
>_______________________________________________
>TRNSYS-users mailing list
>TRNSYS-users at engr.wisc.edu
>https://www.cae.wisc.edu/mailman/listinfo/trnsys-users

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Thermal Energy System Specialists (TESS), LLC
David BRADLEY                           2916 Marketplace Drive - Suite 104
Partner                                        Madison, WI 53719
Phone: (608) 274-2577 USA
Fax: (608) 278-1475
E-mail: bradley at tess-inc.com
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