Call slider values from within another function

I've got the following code setting up a timer object that should take a demical value from a slider (named AlphaSider) convert that into radians and pass that into another angle variable. The idea is that this is done for 4 slider variables and these angles are used to construct a serial link plot with the robotics toolbox. All relevant code (I hope) is below:

L(1)=Link ( [  0     0    1    0     0] )  ;
L(2)=Link ( [  0     0    1    0     0] )  ;
L(3)=Link ( [  0     0   0.1 pi/2 0] )  ;
L(4)=Link ( [  0     0    1    0     0] )  ;
fourlink = serialLink(L,'name', 'four link');

%declare decimal angle variables
global o
global a
global b
global g

%set initial values
o=0;
a=0;
b=0;
g=0;

function runbtn_Callback(hObject, eventdata, handles)
global t
t = timer('TimerFcn', ReadVals, 'ExecutionMode', 'FixedRate', 'BusyMode', 'Queue', 'Period', 0.5);
set(handles.statusdisp,'String', 'Running');

start(t)

function [rado,rada,radb,radg]=ReadVals(o,a,b,g, hObject, eventdata, handles)
global fourlink

o=get(handles.OmegaSlider,'Value');
set(handles.OmegaVal,'Value', o);
rado=(o*pi)/180;

a=get(handles.AlphaSlider,'Value');
set(handles.AlphaVal,'Value', o);
rada=(a*pi)/180;

% etc... for the other two then :

L(1)=Link ( [  0     0    1    0     0] )  ;
L(2)=Link ( [  0     0    1    0     0] )  ;
L(3)=Link ( [  0     0   0.1 pi/2 0] )  ;
L(4)=Link ( [  0     0    1    0     0] )  ;
fourlink = serialLink(L,'name', 'four link');
fourlink.plot([rado rada radb radd]);

function stopbtn-Callback(hObject, eventdata, handles)
global t
stop(t)
set(handles statusdisp,'String', 'Stopped');

Unfortunately when I run this it throws back "Not enough input arguements" Concerning the lines such as "o = get (handles.OmegaSlider,'Value'

When I remove these and just set o = to any number, say 90, and do so with the other 3 angles, the code runs fine and plots the serial plot with all joints at 90 degrees to each other so i know that that aspect of the code should be ok and its just obtaining the values in the first place from the slider. HELP PLEASE?

Thanks in advance

Answer 1

[Walter Roberson]

t = timer('TimerFcn', @(hObject, eventdata) ReadVals(hObject, eventdata, gcf), 'ExecutionMode', 'FixedRate', 'BusyMode', 'Queue', 'Period', 0.5);

function ReadVals(hObject, eventdata, thisfig)
global fourlink
handles = guidata(thisfig);

Note: you cannot return values from callbacks (well, not unless they are filter functions, and those ones do not take the same inputs as other callbacks)

[William]

That's great thanks. Aside from this, when I plot the Serial link just using the code below:

fourlink = serialLink(L,'name', 'four link');

fourlink.plot([rado rada radb radd]);

it automatically plots in the unused axes in my GUI which is perfect, and is where I want it, but when i try to command it to plot there so that I can define another plot in another axes it does not accept it. I've tried using :

fourlink = serialLink(L,'name', 'four link');

fourlink.plot(handles.axes2, [rado rada radb radd]);

as i have used for making polar plots of my angl variables but it returns an error saying only "unknown option:" could you help me with a suitable line for plotting this to a specific axes or let me know where I'm missing some sort of parameter somewhere. Thanks