Re: [TRNSYS-users] Type 70

[David Bradley <bradley@tess-inc.com>]

The documentation for Type70 is quite pathetic - and since I wrote it, I
guess I am allowed to say so. Yes, it is possible to do what you want
using Type70 but I am not sure that it is the best solution. You would
need one external file (containing the value of your one parameter) for
each of your simulations. The problem is that you would then have to
switch external files each time you ran the simulation, which would be
just as time consuming as changing the one parameter. What I would
suggest instead is that you open the input file in TRNEdit and define a
CONSTANT statement for the one parameter variable that is to change. You
can then set up a parametric run and assign as many different values of
that one CONSTANT as you like. The one thing to remember about parametric
runs is that only the output files that have the same name as the input
file will be reproduced (provided that you are not using the Type25
printer in its "append" mode). Make sure that if your .dck is
named "inputfile.dck" that all of the output files have names
like "inputfile.out" "inputfile.ou1"
"inputfile.txt", etc. 

Just for reference, here is some hopefully more useful documentation on
Type70...

5.13.20 Type 70: Parameter replacement
 
Type 70 reads a specified text file and takes the values of variables
found there and inserts them into the correct locations in the
simulation. Type 70 can be used to modify a TRNSYS input file based on
the contents of a file, which can be left behind by any other
program.
 
5.13.20.1 Component configuration
Type 70 is called once during the first time step. It reads a series of
numbers out of a text file (the file is given a logical unit number) and
then inserts those numbers into the main TRNSYS PAR array at the location
specified by the Unit number given in Parameter 3. Type70 can be used to
replace the parameters one or more components in a simulation. The first
parameter of Type70 is the logical unit number assigned to the external
file containing replacement parameter values. Simulation Studio users
need to specify an external file name in the ?external files? tab of the
Type70 proforma. Type70 then takes a two parameters for each component
that is to have its parameter list replaced. The first of these
parameters is the number of consecutive parameters that must be replaced
in a given component. Type70 always starts by replacing the first
parameter but it does not necessarily have to replace all parameters for
a given component. Say, for example, that the user wishes to replace only
the fifth parameter of a given component. The user would specify that 5
parameters must be replaced for that component. The second of the pair of
parameter indicates which component is to have its parameters replaced by
designating its UNIT number. Users of the Simulation Studio will need to
check the component order tab of the ?control cards? tool or press the F2
key in order to find out what UNIT number has been assigned to each
component in the simulation. 
 
The external text file syntax is quite simple; the file will have one
line for each UNIT that is to have its parameters replaced. Each line
simply contains a list of the replacement parameters. To follow on the
previous example, say that UNIT 3 is to have its parameters replaced and
that the parameter list in UNIT 3?s proforma is:
 
1.0  4.0  67.0  2.0  5.0 
 
Recall that we want to change only the value of the fifth parameter. The
single line in the external file might be:
 
1.0  4.0  67.0  2.0  17.0 
 
Which would have the result of changing UNIT 3?s fifth parameter from a
value of 5 to a value of 17.
 
EXAMPLE
A program is written that provides the TRNSYS user with a number of
slider bars to set up a 24 hour repeating schedule. The program is
designed to output a text file (NewPars.txt) containing the 24 selected
values of the sliders. When the simulation is run (by clicking Calculate
or by pressing F8), Type 70 looks for the text file left behind by the
program, reads the values and inserts them into the global PARS array at
the appropriate location. The PARS array is a TRNSYS array that contains
all the values of all the Parameters from all the different Types in the
simulation. Type 70 is only called on the first time step; the newly
modified Parameters will not be changed again during the course of the
simulation. In the example at hand, the values would be inserted as
Parameters for Type 14 (Forcing Function), which has been given UNIT
number 15 in the simulation. The user has set the sliders so that they
all have the value 1.5, and the logical UNIT number assigned to the
slider program output file logical unit 30. The parameter list for Type70
would be:
 
Logical unit number of file containing
parameter:                       
30  
Number of consecutive parameters to be
replaced:                   
24  
The unit number in the deck to which the parameters
belong:     15
 
The file NewPars.txt would have a single line:
 
1.5    1.5  1.5  1.5  1.5  1.5 
1.5  1.5  1.5  1.5  1.5  1.5  1.5 
1.5  1.5  1.5  1.5  1.5  1.5  1.5 
1.5  1.5  1.5  1.5
 




At 04:54 2/12/2007, comi.daniele.poli@alice.it wrote:

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Hello,
I have to simulate a list of simulation, changing the value of one parameter for each simulation. Is it possible to do that automatically using type 70, and how can i write the text file wich containing values of parameters?
Thanks.

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