Juan, I do not really understand your problem. In the deck file you describe, you print one value every 24h, i.e. at time=6, 30, 54, etc. So actually the printer should not interpolate anything at 6.25, 6.5 etc. And I do not understand the reason why you use a simulation time step of 0.05 to read a file with hourly time step and output one value per day... May be the "problem" you are talking about is due to a common misunderstanding about the type9. If you set the data reader to interpolate the data (which you do here for the third output) and if you simply print the values read by the data reader, there will be a difference. This is due to the fact that: - If you set the data reader to interpolate the data, the type9 interpretes the values as instantaneous. - In TRNSYS, all output variables are averaged on the time step. So at time 6 you will read the temperature at 6, but output the average temperature between 5 and 6. This is better explained by an example (NOTE: The example hereunder works in Trnsys14.2, but the attached files give the same example for any Trnsys15 user interested) Assume you have got this input file, Test.dat 0 0 1 1 2 2 ... And this deck file, Test.dck assign Test.lst 6 assign Test.dat 10 assign test.out 11 Simulation 0.0 10.0 1.0 Unit 1 Type 9 Std Data Reader Parameters 10 -2 2 1.0 1 1.0 0.0 -2 1.0 0.0 10 Unit 2 Type 25 Printer Parameters 4 1.0 0.0 10.0 11 Inputs 2 1,1 1,2 Interp NotInt END The output file (Test.out) will be TIME Interp NotInt +0.00000E+00 +0.00000E+00 +0.00000E+00 +1.00000E+00 +5.00000E-01 +1.00000E+00 +2.00000E+00 +1.50000E+00 +2.00000E+00 +3.00000E+00 +2.50000E+00 +3.00000E+00 ... The 1st column is interpolated, even though the simulation time step is the same as the data time step, because outputs are averaged on the time step. I hope this helps you, if not do not hesitate to contact me again Michael PS Your trnshell version is quite old... You can find a more recent one on the SEL website. By the way, you could think to upgrade to Trnsys 15 one of these days... _________________________________________________ Michael Kummert Solar Energy Laboratory - University of Wisconsin-Madison 1500 Engineering Drive, 1303 Engr Res Bldg Madison, WI 53706 Phone: +1 (608) 263-1589 Fax: +1(608) 262-8464 E-mail: kummert@sel.me.wisc.edu SEL Web Site: http://sel.me.wisc.edu TRNSYS Web Site: http://sel.me.wisc.edu/trnsys -----Original Message----- From: owner-trnsys@relay.doit.wisc.edu [mailto:owner-trnsys@relay.doit.wisc.edu]On Behalf Of EXTERN Salazar Juan Pablo (Praktikant; TT/EVT) Sent: Wednesday, November 28, 2001 10:52 To: 'trnsys@relay.doit.wisc.edu' Subject: Interpolation Dear TRNSYS Users, I'm experiencing a quite odd situation. For reasons that do not need to be mentioned, I wrote a very simple Deck that has only one function. It reads meteorogical data from a file and prints the dry bulb temperature as an output. This occurs at a specific time every day. What I observed is that for different hours I became the same temperature. For example: 6h, 6,25 and 6,5. The file has hourly values and they are different between 6 and 7, so that different values should be expected. Once I reduce the time intervall at wich printing is to occur and investigate the temperatures between 6h and 7h TRNSYS interpolates normally. My TRNSHELL version is 1.993 and the Deck is attached below. I hope someone out there can help me out. Best Regards, Juan Salazar *=========================================================================== ===* ASSIGN Temperature.LST 6 ASSIGN Temperature.ou1 29 *=========================================================================== === CONST 12 JAN = 0.0 FEB = 744.0 MAR = 1416.0 APR = 2160.0 MAY = 2880.0 JUN = 3624.0 JUL = 4344.0 AUG = 5088.0 SEP = 5832.0 OCT = 6552.0 NOV = 7296.0 DEC = 8016.0 *=========================================================================== === CONST 11 STARTMONTH = JAN S_MONTHDAY = 1 STARTDAY = STARTMONTH/24.0+S_MONTHDAY STARTHOUR = 6 DURATION = 8736 *=========================================================================== === TimeStep = .05 START = (STARTDAY-1.0)*24.0+STARTHOUR StatTime = START EndTime = START+DURATION PrStart = START *=========================================================================== === SIMULATION StatTime EndTime TimeStep TOLERANCES 0.005 0.005 LIMITS 75 100 60 WIDTH 72 DFQ 2 *=========================================================================== === EQUATIONS 1 T = [1,3] ASSIGN C:\trnwin\weather\wuerzb.try 13 UNIT 1 TYPE 9 Data Reader for TRY PARAMS 20 * Mode #of_values time_interval -2 5 1 * Int Mul Add Int Mul Add Int Mul Add Int Mul Add Int Mul Add LU Format * 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 -1 1 0 -2 1 0 3 1 0 4 1 0 5 1 0 13 1 (6X,F7.2,F7.2,F5.1,F6.1,F3.0) * Outputs [1,#]: # Value * 1 Ib: Beam Radiation in kJ/(hr*m2) * 2 Id: Diffuse Radiation in kJ/(hr*m2) * 3 Tdb: Dry Bulb Temperature in °C * 4 Ws: Wind Speed in km/h * 5 RHR: Ambient Relative Humidity Ratio in % * 19 td1: Time corresponding to values on previous line * 20 td2: Time corresponding to values on next line *========================================================================= UNIT 7 TYPE 25 Printer for each time step PARAMETERS 5 * time_intervall starttime stoptime LU# User_Units=1 24 PrStart ENDTIME 29 1 INPUTS 1 T * input labels T * input units C *--------------------------------------------------------------------------- ---- END
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