1]Change variable value during script is running 2] while running Script in loop does not update variable value in workspace

I am controlling a pilot plant of boiler through Matlab using modbus RTU (serial communication).I am running my control program (in editor) for 45 mins through a loop but I am facing two problems 1] I can't change any variable value while running program which is deadly needed. 2] I am unable to see real time data in workspace while running script. It updates all variables after finishing execution time. For my application I want data to appear for every iteration.

I couldn't solve them so I switched to simulink but that was even more frustrating.In simulink i used user defined blocks (embedded Matlab function) to generate modbus address PDU which does not support to in-built matlab functions (like dec2hex).Will please someone let me know in simulink, serail send/receive support which data formate?(ASCII/HEX/DEC)

Will please someone guide me for these problems? I am near to end my patience.

Thank you in advance.

[David Powers]

Really need to write our own gui to do this. But you can use the debugger using dbstop, e.g. stop every 10th time it reaches line 8: dbstop in test_workspace.m at 8 if mod(X,10)==0

You can change variables and continue.

A better approach is to use input which allows you to evaluate an expression and input it to a variable.

But still it requires stopping - but you might be able to use pmode and have one thread for enquiry while the others continue.

Answer 1

[Walter Roberson]

In order to change variable values, the control program needs to retrieve the value from a shared location, and the control program needs to occasionally give the GUI a chance to interrupt for a moment in order allow the GUI to set the shared value. Then you have a callback in the GUI that sets the new value. The routine that the control program needs to use in order to give the GUI a chance to update values is drawnow().

http://matlab.wikia.com/wiki/FAQ#How_can_I_share_data_between_callback_functions_in_my_GUI.3F

To have data appear every iteration, disp() it, or fprintf() it.

[Tejaswini]

Thank you for reply. Problem is I can read either write on serial port on one time . If I change variable value while executing script in loop will it update?

[Walter Roberson]

If the changed data is coming from the serial port, you could use the serial object BytesAvailableFcn callback to set a shared variable that your computation code specifically looks at from time to time.

[Tejaswini]

Thank you for your response.It helped me.