MATLAB Simulink communication in real time

Hi, In my simulink model I am reading a variable's value from MATLAB workspace. Now if I change that variable's value in workspace while simulink is running, then simulink does not get the updated value. It keeps reading the preassigned value. Is there any way by which simulink model can get updated values from MATLAB workspace in real time (without using RT licence or xPC target)

Thanks Mitesh

Answer 1

[Nirmal Gunaseelan]

One way to tune the parameter based on a change in a variable in the MATLAB workspace is to 'update' the model while it is still simulating (Ctrl+D). What is your use case? Are you controlling the model simulation from another MATLAB script?

[Fangjun Jiang]

Nice. Glad to know that. I just tired and it worked. I didn't know before that you can update the diagram while the simulation is running.

[Nirmal Gunaseelan]

It essentially is the same internal process as your suggestion - when you change a block's tunable parameter in the dialog during simulation, an update automatically happens.

[Mitesh Farsodia]

@Nirmal

Yes, I have a GUI and I will be changing that variable's value from GUI. So when I make change on GUI that value goes to MATLAB's workspace and simulink model has to read that value from workspace.

[Nirmal Gunaseelan]

@Mitesh

Good. In that case, you could add an update command to your model in the callback in addition to changing the variable in the workspace. You could use options 12, 13 or 14 in this command line functionality page - http://www.mathworks.com/support/tech-notes/1900/1903.html

[Mitesh Farsodia]

@Nirmal

Thanks, I will try these options and will let you know.

[Arnaud Miege]

I would use the set_param option to change the value of block directly rather than change the value of a parameter in the base workspace.

[Mitesh Farsodia]

@Nirmal and Arnaud

I am trying the syntax

set_param('simulinkmodel/blockname','variable','update')

it's not updating automatically, also when I try ctrl+d it doesn't update. Please correct me if I am making any mistake.

Thanks

[Fangjun Jiang]

It is set_param(YourModelName,'simulationcommand','update').

Make your model your current active window, press Ctrl+D, it should update.

[Mitesh Farsodia]

Thanks Frangiun for your suggestion.

When we do this,it tries to update whole simuling model. I have GT power link in my simulink model and when I tried to update some particular block in my simulink model, it updates that particular block and stops the simulation after that. I am assuming at the same moment it is also trying to update that GT poer block, which stops the simulation. Can we update any particular block name without affecting other blocks in model.

[Fangjun Jiang]

When the model is updated, it is updating the whole model. You need to re-think what you really want. All the approaches talked about above will cause the model to pause, update and then continue. You could leave the simulation continue running while you change the gain of a Gain block, for example. Try that and come back with your true intent.

Answer 2

[Andreas Goser]

Many people with this description look for a way that is actually an artificial slowdown of Simulink, so that it is running approximately in sync with real time.

The are solutions on FileExchange for that, e.g. this one

Answer 3

[Fangjun Jiang]

Use a Constant block in your Simulink model. While your simulation is running, you can double click the Constant block and change its value. The simulation will pause and then continue with the new Constant block value.

Answer 4

[Dharmendra singh]

One way to tune the parameter based on a change in a variable in the MATLAB workspace is to 'update' the model while it is still simulating (Ctrl+D). What is your use case? Are you controlling the model simulation from another MATLAB script?

satisfiefd with reply but not so much

[Kaustubha Govind]

Dharmendra: Perhaps you could provide more information on how Nirmal's answer did not help you? The answer is clear and complete as far as I can see.

Answer 5

[Tan Phat Nguyen]

Sensor 1 (pressure sensor attached to bottom of tank 1) connects to Pin 0 Arduino Uno Sensor 2 (pressure sensor attached to bottom of tank 2) connects to Pin 2 Arduino Uno When running individually, the Volt value and water level return are correct reality. But when running both Volt = 0, water level = 0. So how do I read at the same time two analog values? Thank you