I could swear that I have seen a constant block in Simulink with a vector in its value field and that the effect was that on each simulation time step, Simulink would index the next value in that array and output it on the Constant block's output (see picture below). So the output of the constant block (in the picture below) would be 1, then 2, then 3, then 4.
However, the effect is (regardless of the value of "interpret vector parameters as 1-d"), that only the first value in the Constant block's array is output from it.
I'm I mistaken? What am I doing wrong?
You haven't seen the Constant block behave that way, because it doesn't behave that way. If you want the signal to change then you need to use a block that allows/forces you to also specify a time vector of points indicating when the input values change, such as something like the From Workspace block.
The way you have your model set up, the Constant output is a 4 element vector, as is the output of the Product block.
Also, as per the image you have shown, you are not seeing "that only the first value in the Constant block's array is output from it". The viewer clearly shows that you are viewing the value of Constant 1(1,1), that is the first element in the signal. The other 3 values output from the constant block and the Multiply block are clearly indicated in the viewer, you just haven't selected them for viewing.
Related
Im trying to do some calculations in a Matlab (R2015b) Simulink function block. I use a signal that gives discrete values in 1-minute intervals.
What i want to do is store the signal values of 1 day (1440 values), convert them into a vector and input it in my Matlab function for calculation (getting time between first and last value > x). All while the simulation is running.
Unit delay, and Transport delay blocks wont work because i need all the stored values at once.
Any ideas on this are much appreciated!
Thanks!
You need to add a "To Workspace" block to your simulink diagram. Setting the options as you wish will allow you to save all the outputs in a single vector. You can select the variable's name, and the default is "simout".
Then, after running the diagram, you have the variable you want in the workspace (as if you had typed it in the console). So next, you can call your function with the argument.
I have a model with n blocks connected in series (And last (nth) block's outputs are connected to first block inputs). Only difference among them is the parameter's value (first array element in matlab is value for first block's parameter, second value for the second block and so on). How can I implement it without explicitly copying blocks? What I have now:
I want to have this:
how to use the "from workspace block in simulink" ?
I have tried using the from workspace block by given 10*2 matrix as input. it is appending some extra data along the data I have given .
and I have such 3 such blocks and want to know how I merge them.
Read the documentation. Simulink is time-based so the data in your From Workspace block must be as a function of time. Does your 10 x 2 matrix represent a signal as a function of time? If so, it needs to be as follows:
A two-dimensional matrix:
The first element of each matrix row is a
time stamp.
The rest of each row is a scalar or vector of signal
values.
The leftmost element of each row is the time stamp of the
value(s) in the rest of the row.
10 values isn't very much, it's likely that Simulink will need additional data points at intermediate times, if you have the Interpolate Data check box ticked. If not, "the current output equals the output at the most recent time for which data exists".
I think you may have a misunderstanding of the variables intended to be read by the FromWorkspace block.
The block expects a time series defining the value at various points in the simulation.
The From Workspace block help should point you in the right direction on this. Mathworks Help Documentation
I believe that something like the following would work for you:
>> WorkspaceVar.time=0;
>> WorkspaceVar.signals.values=zeros(10,2)
>> WorkspaceVar.signals.dimensions = [10,2]
I am trying to simulate throw of the ball under angles using simulink. I'm able to simulate it for one angle but I would like to simulate it using loop. This is what I want to do in simulink using FOR :
for i=-5:10:85
Here is picture of my simulink:
If I understand your question correctly, you essentially want to rerun your simulation multiple times for different values of the constant Degrees. Instead of using a For Iterator, you may be able to achieve effectively the same result by using vector operations. That is to say, change the value of the constant Degrees from being a scalar value to instead being a vector (in this particular case just set its value to be [5:10:85]). The outputs of your Simulink model (ie the x and y results) should now be vectors corresponding to the various Degree values.
Put all the blocks into the for-iterator subsystem. The For Iterator block will output the current iteration, you can use that index (which starts at 0/1) to cycle the angle from -5 to 85 (try to hook the For Iterator block up to a Gain and Sum block). At each iteration, all the blocks in the for-iterator subsystem will run, and the output of the For Iterator block will increment by one.
The previous solution to make the angles a vector will also work.
Using MATLAB's for reference page, I'd rewrite your line as:
for i=5:10:85
...
end
I'm having a problem sending a value from a GUI to an Embedded MATLAB Function (EMF) in a Simulink model. I get this value from a slider in my GUI and send it to an EMF block in my model. I can confirm that the value is being transferred correctly from my GUI to my Simulink block, since I can display the value with a display block in my model and see the value change when I change the slider position in my GUI. However I keep getting this error when I run my model:
Could not determine the size of this expression.
Function 'Kastl' (#18.282.283), line 14, column 1:
"f"
This is part of my EMF block code:
function y = input_par(u,fstart)
...
f_end = 1000;
f = fstart:f_end;
...
I believe MikeT is correct: you can't redefine the size of a variable in an embedded function. If you look at this Embedded MATLAB Function documentation page under the subsection Defining Local Variables, it says:
Once you define a variable, you cannot
redefine it to any other type or size
in the function body.
You will have to rework your embedded function such that the variables you declare are not changing size. Since I don't know what you are subsequently doing with the variable f, there's not much more specific help I can give you.
In general, if you absolutely need to use data that changes size, one solution is to pad the data with "garbage" values in order to maintain a constant size. For example:
MAX_ELEMS = 1000; % Define the maximum number of elements in the vector
f = [fstart:MAX_ELEMS nan(1,fstart-1)]; % Create vector and pad with NaNs
In the above example, the variable f will always have 1000 elements (assuming the value of fstart is an integer value less than or equal to 1000). The value NaN is used to pad the vector to the appropriate constant size. Any subsequent code would have to be able to recognize that a value of NaN should be ignored. Depending on what calculations are subsequently done in the embedded function, different pad values might be needed in place of NaN (such as 0, negative values, etc.).
I believe the issue you are running into is that you can't change a parameter during simulation that will cause the dimension of a signal to change. In your example, the code,
f = fstart:f_end;
changes size whenever fstart changes. I think this is what EMF block is complaining about. I don't have any easy workaround for this particular issue, but maybe there's an equivalent way of doing what you want that avoids this issue.