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]
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 am using both MATLAB and LabVIEW for Lab of course of control systems engineering and I want to implement a block diagram(system) in MATLAB and also in LabVIEW
Front panel shows "time response parametric data" which contains 6 parameters fields including settling time ,but i also need settlingMin and settlingMax which are provided/shown in MATLAB by using command stepinfo but i couldn't find a way how to get these two parameters settlingMax and settlingMin in LabVIEW.
Here is MATLAB code
clc
clear all
close all
sys1=tf([10],[1 1])
sys2=tf([1],[2 0.5])
sys_series=series(sys1,sys2)
sys_feedback=feedback(sys_series,0.1)
sys=series(540,sys_feedback)
sys_cl=feedback(sys,1,-1)
step(sys_cl)
stepinfo(sys_cl)
Download link LabVIEW VI
Comparing the help for the LabVIEW VI you are using with the help for the MATLAB function it seems obvious that MATLAB's SettlingMax is the same as LabVIEW's Peak Value in the Time Response Parametric Data cluster, while SettlingMin is the minimum value of the time response signal after Peak Time.
To get the latter value it looks as if you need to:
use CD Get Time Response Data to get the time points and response signal as DBL arrays - I assume Input and Output are both 0 since you have only one signal
use Search 1D Array with the time point array and the Peak Time value to get the array index of the peak time
use Array Subset to select the part of the response array from that index onwards (leave length unwired)
use Array Max & Min to get the minimum value of this array
I have a matrix (type:double) of size 106 x 103. The matrix represents European gridded temperature data for one timestep (a day).
For every day, I want to calculate the degree days (thermal time) for a species, based on the temperature recorded for each 'cell' (i,j element) in the matrix using a formula that I have coded in Matlab based on a sinewave approach.
So, ultimately, what I want to do is being able to apply a calculation to my matrix, that will provide individual output for each grid cell (i,j element) dependent on the temperature data that is recorded there.
I could do this with a loop, but I have to accumulate these degree days for multiple years, so I would prefer to find a way of applying the calculation to each element in a daily matrix simultaneously (and then looping through the days (matrices)).
From what I have read, you can use a cellfun if your matrix is a cell array (mine is not).
Then I was also looking at the bsxfun option, but it seems like the functions are just standard functions..like mean, max etc.
So now, I'm looking at using arrayfun in conjunction with a function I create from my algorithm to calculate degree days.
I have been trying to write a test function but Matlab keeps throwing up the same error:
I type:
function output=degreedays(x)
and Matlab throws back:
Error: Function definitions are not permitted in this context.
Can someone tell me what I'm doing wrong? Why is it not accepting the declaration of the function name?
MATLAB does not allow you to define named functions like this at the command line. You need to place your function definition in a file. MATLAB then can call that function by the name of the file - so in your case, put your function definition in a file called degreedays.m.
See the doc for more: https://uk.mathworks.com/help/matlab/matlab_prog/create-functions-in-files.html .
I'm trying to model the respective processes of an internal combustion engine. My current modelling approach is to have different sub functions which model the different processes.
Within each sub function is a Level 2 S-Function which solves the ODEs to give the in cylinder state (pressure, temperature, etc).
The problem that I'm having is that each sub function is enabled depending on the current crank angle which is computed from the current timestep in Simulink. The first process works fine as I manually set the initial values, but then I can't pass the latest in-cylinder state (the output from the first sub function) to the second sub function to use as the initial conditions (it insists on using the initial values I set at the beginning of the simulation).
Is there any way round this? Currently I'm going along a path of global data stores, but haven't had any joy so far.
There are a lot of different ways to solve this problem.
I'll show some of them as examples.
You can create additive output with Unit dalay block like this:
So you can get value of your crank angle from previous timestep and USE IT in formula for solving you equations.
Also you can use some code like this:
if (t == 0)
% equations with your initial values
sred = 0;
else
% equations with other values
y = uOld + myCoeef;
end
Another idea: sometimes I use persistent variables in Matlab function to save values of some variable from previous step. But I think it makes calculation slower.
One more idea - if you have Stateflow you can create chart with two states: first for initial moment with your coefficient and second to solve new equations.
If I understood you in wrong way you can show your code and we'll offer some new ideas!
P.S. Example of my using of S-Function:
My S-Function needs 2 values: Q is calculated in simulink at every step, ro is initial I took from big matrix I loaded from workspace in table and took necessary value depending of time.
So there is no any initial values in S-Function - all needed values I transmit into it from simulink!
I am trying to evaluate with iddata (INFO) in matlab, a number of N_E experiments.
I already computed and have as cell arrays of size 1xN_E the outputs and inputs, y and u respectively. Every entry of the cell arrays y and u is a vector of length N=316 (SISO system). For the sake of correctness, period is also a cell array of size 1xN_E, with the period in every entry.
Using the command:
data = iddata(y,u,period);
doesn't produce the expected averaged data-set. Instead, it is handled as a 361x361MIMO system (!).
I've already tried transposing, without results.
data = iddata(y.',u.',period.');
Does someone know why this happens, and how can I produce the desired multi-experiment data-set?
P.S. the documentation I read is for Matlab R2014b, and I am running R2013b. Does someone know if this was not supported in my edition? Or how can I find out?
Actually, the Matlab documentation provides an answer to my question.
The function iddata is very strict regarding how the dimension of output y, input u and period period are defined.
Defining 1xN_experiments cell arrays for y,u and period (note: same size for all!; also N_experimentsx1 won't be recognized by iddata) and then using iddata:
data = iddata(y,u,period);
gives the desired iddata structure.
Note all vectors within y and u must be of same length(!)