how to control stepper motor speed via USB port

Question

fremond khoo 2011-3-27

2
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port

i really need some help over here..i have connected and run my stepper motor but how come i cannot control the speed of my motor?..can someone give me some hints?

below are my coding:

    function text_speed_m1_Callback(hObject, eventdata, handles)
  sliderValue = get(handles.text_speed_m1,'String');
%convert from string to number if possible, otherwise returns empty
sliderValue = str2nm(sliderValue);
%if user inputs something is not a number, or if the input is less than 0
%or greater than 100, then the slider value defaults to 0
if (isempty(sliderValue) || sliderValue < 0 || sliderValue > 256)
    set(handles.slider_speed_m1,'Value',0);
    set(handles.text_speed_m1,'String','0');
else
    set(handles.slider_speed_m1,'Value',sliderValue);
end
% --- Executes during object creation, after setting all properties.
function text_speed_m1_CreateFcn(hObject, eventdata, handles)
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
    set(hObject,'BackgroundColor','white');
end
% --- Executes on slider movement.
function slider_speed_m1_Callback(hObject, eventdata, handles)
sliderValue = get(handles.slider_speed_m1,'Value');
%puts the slider value into the edit text component
set(handles.text_speed_m1,'String', num2str(sliderValue));
% Update handles structure
guidata(hObject, handles);
% --- Executes on button press in pushbutton_speed_m1.
function pushbutton_speed_m1_Callback(hObject, eventdata, handles)
obj1 = instrfind('Type','serial','Port','COM8','Tag','');  
if isempty(obj1)
    obj1 = serial('COM8');
else
    fclose(obj1);
    obj1 = obj1(1)
end
fopen(obj1);
sv2 = get(handles.text_speed_m1,'String');
fprintf(obj1,'%s','rs')
fprintf(obj1,int2str(get(hObject,'Value')));

please give me some hints on what i do wrong..really need help now..thanks

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Walter Roberson 2011-3-27

Please reformat your code to be more readable. If you go in to the editor and select the code and press the '{} Code' button then it will be reformatted.

Please also check that the code output is what you wanted. For example one of your lines shows up as "if (isempty(sliderValue) sliderValue < 0 sliderValue > 256)" which is invalid syntax. I suspect that you had or-bar there but that your or-bar was interpreted by the forum as formatting instructions.

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Answer 1

Walter Roberson 2011-3-27

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_5775

We can't tell why you cannot control the speed of the motor. You have not described what happens when you try.

Closing and reopening the serial port each time is not advisable. If you find a serial port and it is open, then you should use it.

In your code, if obj1 is empty after the instrfind, then when you associate the serial port with obj1, you have omitted setting anything like port speed. The default probably is not what you want; even if it happens to be, other people reading your code are going to be left wondering and the defaults might change in other versions, so it is better to set port characteristics explicitly.

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Answer 2

fremond khoo 2011-3-27

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_5786

在 MATLAB Online 中打开

thanks walter for the advice, i have altered my coding but the error is still there..

function text_speed_m1_Callback(hObject, eventdata, handles) 
val = str2num (get(handles.text_speed_m1,'String')); 
set(handles.slider_speed_m1,'Value',val);
%convert from string to number if possible, otherwise returns empty 
sliderValue = str2num(sliderValue); 
%if user inputs something is not a number, or if the input is less than 0 
%or greater than 100, then the slider value defaults to 0 
if (isempty(sliderValue) || sliderValue < 0 || sliderValue > 256) 
set(handles.slider_speed_m1,'Value',0); 
set(handles.text_speed_m1,'String','0'); 
else 
set(handles.slider_speed_m1,'Value',sliderValue); 
end
% --- Executes during object creation, after setting all properties. 
function text_speed_m1_CreateFcn(hObject, eventdata, handles) 
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor')) 
set(hObject,'BackgroundColor','white'); 
end
% --- Executes on slider movement. 
function slider_speed_m1_Callback(hObject, eventdata, handles) 
val = get(handles.slider_speed_m1,'Value'); 
set(handles.text_speed_m1,'String',num2str(val));
obj1 = instrfind('Type','serial','Port','COM9','Tag','');
if isempty(obj1) 
obj1 = serial('COM8');
fopen(obj1); 
fprintf(obj1,'%s\n','S');
end 
fclose(obj1); 
%puts the slider value into the edit text component 
set(handles.text_speed_m1,'String', num2str(sliderValue));
% Update handles structure 
guidata(hObject, handles);

the error shown when i move the slider is:

??? Error using ==> serial.fopen at 72 
Port: COM8 is not available. Available ports: COM3. 
Use INSTRFIND to determine if other instrument objects 
are connected to the requested device.
Error in ==> GUI_xyplotter>slider_speed_m1_Callback at 
479 
fopen(obj1);
Error in ==> gui_mainfcn at 96 
feval(varargin{:});
Error in ==> GUI_xyplotter at 16 
gui_mainfcn(gui_State, varargin{:});
Error in ==> 
@(hObject,eventdata)GUI_xyplotter('slider_speed_m1_Callback',hObject,eventdata,guidata(hObject))
??? Error while evaluating uicontrol Callback

and can i ask what do you mean by "invalid syntax"?

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fremond khoo 2011-3-28

can someone teach me how to solve this problem?..im really short of time..really hope to get some advices and help..

Walter Roberson 2011-3-28

Doesn't this case correspond to you closing the existing port and opening it again? Or did you remove that code?

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Answer 3

fremond khoo 2011-3-29

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https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_5935

在 MATLAB Online 中打开

Mr walter, my senior give me another different code to control the speed by using decimal to binary code such as this:

% --- Executes on button press in pushbutton_speed_m1.
function pushbutton_speed_m1_Callback(hObject, eventdata, handles)
sv2 = get(handles.text_speed_m1,'String');
a = dec2bin(83,8);
b = dec2bin(sv2);
c = [a b];
fwrite(obj1,c,'int16')

but when i try to execute the pushbutton to set the speed, a different error occur:

??? Error using ==> horzcat
CAT arguments dimensions are not consistent.
Error in ==> GUI_xyplotter>pushbutton_speed_m1_Callback
at 614
c = [a b];
Error in ==> gui_mainfcn at 96
        feval(varargin{:});
Error in ==> GUI_xyplotter at 16
    gui_mainfcn(gui_State, varargin{:});
Error in ==>
@(hObject,eventdata)GUI_xyplotter('pushbutton_speed_m1_Callback',hObject,eventdata,guidata(hObject))

i dun quite understand the function of dec2bin(83,8) means and what is the error of this codes..can you help me?..thanks

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Walter Roberson 2011-3-29

That code seems highly unlikely to work, but here is the code you would need to change:

b = dec2bin(sv2,8);

c = reshape([a;b] .', 1, []);

I would be startled fwrite(obj1,c,'int16') produces the result you are hoping for. Please re-check to see whether your senior had a bin2dec() call after c was created. Please also recheck to see if your senior converted a 10 (linefeed) or 13 (carriage return)

Your senior's code seems to be created with the idea that you send 'S' followed by a _single_ character to indicate the speed, except that the code doesn't actually do that.

Are you aware that in your original code, you do not send any value derived from the slider after the 'S'? You carefully build "val" but do not sent it to the COM port.

Please cross-check exactly what format of numbers the motor control expects. I do not see anything in your code that would restrict val to being an integer. With the range of values you are restricting to, and the code your senior provides, I wonder whether what the motor control is expecting is 'S' followed by a single byte whose decimal equivalent is the number of 1/255 of full speed -- e.g., byte value 0 for stop, byte value 128 for half speed, byte value 255 for full speed. If so then your senior's code starts to hint at some sense (but would still not be correct in the form posted.)

fremond khoo 2011-3-31

im sorry walter for the late reply..i have been busying with the assembly and modifications of my robot arm..

i have checked my senior code..he does not have a bin2dec() call after c was created..his code is simply based on what i have shown above..btw i have changed the

b = dec2bin(sv2,8);

c = reshape([a;b] .', 1, []);

but still nothing happens..can you enlighten me more? and about the 'S' to control motor speed..my senior said he took from a VB source code saying the command 'S' is supposed to control the speed of the motor. Like command 'B' is the command for brake..How should i write my coding to make sure i can control my motor speed based on my senior code?..i have altered some parts of my senior code but still no luck..once again, really hope can get some help from you..

thanks a lot for your time

Walter Roberson 2011-3-31

Is there a reference document that discusses the command format expected by the motor?

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Answer 4

fremond khoo 2011-3-31

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https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_6235

在 MATLAB Online 中打开

actually i dont have any reference document that discusses the command format expected by the motor..but i have the coding of visual basic which i got from my senior..he said he refer to that code to run his motor..

the code is:

Private Sub hsbSPEED_scroll( _ 
ByVal sender As Object, ByVal e As System.EventArgs) _ 
Handles hsbSpeed.Scroll
txtSpeed.Text = CStr(hsbSpeed.Value) 
data(0) = CByte(hsbSpeed.Value)
SerialPort.Write("S") 
SerialPort.Write(data, 0, 1)
End Sub

i used the visual basic code to control my stepper motor speed and it work well..so, walter does this code means anything?

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fremond khoo 2011-4-1

walter..i want to ask how do you know what code to write after looking at the visual basic coding which i paste above?..how do you convert them into matlab coding?..can you teach me about that?..

Walter Roberson 2011-4-1

It was through experience, Fremond. Without looking it up, I could see that CByte was obviously a "convert to byte" call, and the matlab equivalent of converting to byte is uint8()

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Answer 5

fremond khoo 2011-4-2

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在 MATLAB Online 中打开

oh..i understand now..so if i want to track my encoder value is also the same right?..the visual basic code is around the same with controlling the speed..

    Private Sub btnTrack_Click( _
        ByVal sender As System.Object, ByVal e As System.EventArgs) _
        Handles btnTrack.Click
        data(0) = CByte((CLng(nudTrack.Value) >> 8) And &HFF)   'High byte
        data(1) = CByte(CLng(nudTrack.Value) And &HFF)          'Low byte
        SerialPort.Write("T")
        SerialPort.Write(data, 0, 2)
    End Sub

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fremond khoo 2011-4-4

thanks walter..really thanks a lot..cheers!!

Walter Roberson 2011-4-7

In the above,

t1 = num2str(get(handles.text_track_m1,'String'));

should instead be

t1 = str2num(get(handles.text_track_m1,'String'));

or one of its equivalents. str2double() is better than str2num()

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Answer 6

fremond khoo 2011-4-6

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https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_6871

在 MATLAB Online 中打开

im sorry walter..i got another thing to ask you..i have asked my senior and he also dun knw how to program for this..I dun knw how to write the condition for this microstepping process..i need to change the microstep to 1/10 means 0.18 degree per step for my motor..can u help me?..thanks

here is the code:

Private Sub btnMstep_Click( _
        ByVal sender As System.Object, ByVal e As System.EventArgs) _
        Handles btnMstep.Click
          If cbbMicroStep.Text = "None (1 / 1)" Then
              data(0) = CByte(1)
          ElseIf cbbMicroStep.Text = "1 / 2" Then
              data(0) = CByte(2)
          ElseIf cbbMicroStep.Text = "1 / 5" Then
              data(0) = CByte(5)
          ElseIf cbbMicroStep.Text = "1 / 10" Then
              data(0) = CByte(10)
          End If
          SerialPort.Write("M")
          SerialPort.Write(data, 0, 1)
      End Sub
End Class

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fremond khoo 2011-4-7

walter..i changed into using listbox but got error:

??? Error using ==> strcmp

Too many output arguments.

Error in ==> GUI_xyplotter>pushbutton_ms_m2_Callback at

641

[tf,idx]=strcmp(M2,{'None(1/1)','1/2','1/5','1/10'});

Error in ==> gui_mainfcn at 96

feval(varargin{:});

Error in ==> GUI_xyplotter at 16

gui_mainfcn(gui_State, varargin{:});

Error in ==>

@(hObject,eventdata)GUI_xyplotter('pushbutton_ms_m2_Callback',hObject,eventdata,guidata(hObject))

??? Error while evaluating uicontrol Callback

what it means?..too much output argument?

Walter Roberson 2011-4-7

Sorry, I misused strcmp. I should have written

tf = strcmp(t1, {'None (1 / 1)', '1 / 2', '1 / 5', '1 / 10'});

if any(tf)

stepfactor = stepfactors(idx);

fwrite(obj1, [uint8('M') uint8(stepfactor)];

else

%warn about the text not being what was expected

end

With a listbox, you would use this as the body of the callback:

stepfactors = [1 2 5 10];

idx = get(hObject,'Value');

if ~isempty(idx)

stepfactor = stepfactors(idx);

fwrite(obj1, [uint8('M') uint8(stepfactor)];

end

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Answer 7

fremond khoo 2011-4-7

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https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_6916

在 MATLAB Online 中打开

did i write the wrong code?..
fopen(obj2);
L2 = [1 2 5 1 0];
M2=get(handles.listbox2,'String');
[tf,idx]=strcmp(M2,{'None(1/1)','1/2','1/5','1/10'});
if tf
    stepfactor=L2(idx);
    fwrite(obj1,[uint('M') uint8(L2)]);
else
fprintf('Sorry,unable to microstep');
end

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fremond khoo 2011-4-7

i know why already..because i do not know the encoder value so i could not track the movement of the motor..i used the C++ code to find the encoder value but the value comes out to be a very large number..something like 2000 then to 8000..When i put the track value to be 3500 the motor will stop exactly at that number..

i have converted the 'receive encoder' code to matlab code..i try to run it..matlab shows no error but unfortunately there is no value comes out from my textbox..did i set the wrong code?

fremond khoo 2011-4-7

erm..wait for a while walter..i try to edit the code again first^^

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Answer 8

fremond khoo 2011-4-7

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https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_6993

在 MATLAB Online 中打开

Im sorry walter..in the end..i still cant change the code from C++ to matlab form..i try the same way like tracking command..but i used fscanf to get the data and want to put the value in the edit textbox..the code is around the same like track function:

   Private Sub btnAcquire_Click( _
          ByVal sender As System.Object, ByVal e As System.EventArgs) _
          Handles btnAcquire.Click
          SerialPort.Write("E")
          Dim recH As Integer = ((SerialPort.ReadByte() << 8) And &HFF00) 'High byte
          Dim recL As Integer = (SerialPort.ReadByte() And &HFF)          'Low byte
          txtEncoder.Text = CStr(recH Xor recL)                           'Combined to a 16 bits value
      End Sub

can i again ask too much of your help walter?

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fremond khoo 2011-4-7

can i ask what does it mean by

t=fread(obj1,2,'uint8');

what does the number '2' define?

Walter Roberson 2011-4-7

The 2 means to read two items; each item will be of type uint8.

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Answer 9

fremond khoo 2011-4-7

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https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_7009

在 MATLAB Online 中打开

thanks a lot Mr walter..i can acquire encoder value already but how to track the encoder value to stop the motor..the code is:

 function text_track_m2_Callback(hObject, eventdata, handles)
% --- Executes on button press in track_m2.
function track_m2_Callback(hObject, eventdata, handles)
obj2 = instrfind('Type','serial','Port','COM9','Tag','');  
if isempty(obj2)
    obj2 = serial('COM9');
end
fopen(obj2);
t2 = get(handles.text_track_m2,'String');
tval16 =uint16(t2);
tval16H = tval16/256;
tval16L = tval16-tval16H*256;
fwrite(obj2,[uint8('T'),uint8(tval16H),uint8(tval16L)]);

did i define something wrong?

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Walter Roberson 2011-4-8

Insufficient information. No correspondence has been documented between angles and the values sent for the 'T' command.

fremond khoo 2011-4-8

ic..ok..thanks a lot walter for your help..i will try to find out more info in the mean time..thanks^^..

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Answer 10

fremond khoo 2011-4-8

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https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_7065

在 MATLAB Online 中打开

im sorry walter..i face some sort of malfunction when trying to receive the encoder value for motor 2..my coding format follows exactly like motor 1 but somehow it comes out this error:

Warning: The specified amount of data was not returned
within the Timeout period. 
??? Attempted to access t(1); index out of bounds
because numel(t)=0.
Error in ==> GUI_xyplotter>request_m2_Callback at 569
output=uint16(t(1))*256+uint16(t(2));
Error in ==> gui_mainfcn at 96
        feval(varargin{:});
Error in ==> GUI_xyplotter at 16
    gui_mainfcn(gui_State, varargin{:});
Error in ==>
@(hObject,eventdata)GUI_xyplotter('request_m2_Callback',hObject,eventdata,guidata(hObject))
??? Error while evaluating uicontrol Callback

motor 2 code:

fopen(obj2);
fwrite(obj2,uint8('E'));
t=fread(obj2,2,'uint8');
output=uint16(t(1))*256+uint16(t(2));
set(handles.text_request_m2,'String',output)

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Walter Roberson 2011-4-10

There are some suggestions about learning MATLAB in a previous Question, http://www.mathworks.com/matlabcentral/answers/1148-how-to-learn-matlab

It would be fairly difficult these days to get the same kind of experience that I got -- I've been programming for 35 years, from the days when I was the only person in my class who could afford to buy a computer that could fit as many as 99 instructions...

fremond khoo 2011-4-10

woa..35 years??..think i can never get the same kind of experience like you..but anyhow..i will try my best to understand more..thanks..^^

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Answer 11

fremond khoo 2011-4-11

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https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_7321

在 MATLAB Online 中打开

Walter..i have a question for you..do you still remember the first time you help me in the connection of the motor?..

you gave me this code:

function obj=find_and_open(port,wantbaud)
obj = instrfind('Type','serial','Port',port);
if isempty(obj);
    obj = serial(port);
end
if get(obj,'BaudRate')~=wantbaud
    if strcmpi(get(obj,'Status'),'open');
        fclose(obj);
    end
      set(obj,'BaudRate',wantbaud);
  end
if ~strcmpi(get(obj,'Status'),'open');
    fopen(obj);
end

i want to ask this code should be place first before any pushbutton is callback right?..after i have define the obj, i should be able to connect to the COM by writing code like this right?

% --- Executes on button press in connect_m1.
function connect_m1_Callback(hObject, eventdata, handles)
%Create a serial port object
obj1 = find_and_open('COM8',9600);
handles.obj1=obj1
guidata(hObject,handles)

thereafter..if i want to control other buttons..can i just write like this?

     % --- Executes on button press in on_m1.
  function on_m1_Callback(hObject, eventdata, handles)
  obj1 = instrfind('Type','serial','Port','COM8','Tag','');  
fprintf(obj1,'%s\n','O');

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fremond khoo 2011-4-11

obj2 = find_and_open('COM9',9600)

im also confuse what went wrong..what about the object properties?..do i need to change anything about that?

Walter Roberson 2011-4-11

Put that fprintf() statement in a try/catch block, and when the exception occurs, display the output of get(obj2) in order to see what the internal status of the object was.

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Answer 12

fremond khoo 2011-4-12

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https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_7405

在 MATLAB Online 中打开

before that, walter..can i arrange my code like that?..or the arrangement is totally wrong?

%find and open serial port
function obj=find_and_open(port,wantbaud)
obj = instrfind('Type','serial','Port',port);
if isempty(obj);
    obj = serial(port);
end
if get(obj,'BaudRate')~=wantbaud
    if strcmpi(get(obj,'Status'),'open');
        fclose(obj);
    end
      set(obj,'BaudRate',wantbaud);
  end
if ~strcmpi(get(obj,'Status'),'open');
    fopen(obj);
end
% --- Executes on button press in connect_m1.
function connect_m1_Callback(hObject, eventdata, handles)
%Create a serial port object
obj1 = find_and_open('COM8',9600);
% --- Executes on button press in connect_m2.
function connect_m2_Callback(hObject, eventdata, handles)
%Create a serial port object
obj2 = find_and_open('COM9',9600);

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fremond khoo 2011-4-12

walter..i use ur way of using try and catch function and it work..now i can control two motor at the same time^^..cheers!!..the only prob left is still the receive encoder..always comes out the same error:

??? Attempted to access t(1); index out of bounds

because numel(t)=0.

Error in ==> GUI_xyplotter>request_m2_Callback at 280

output=uint16(t(1))*256+uint16(t(2));

Error in ==> gui_mainfcn at 96

feval(varargin{:});

Error in ==> GUI_xyplotter at 16

gui_mainfcn(gui_State, varargin{:});

Error in ==>

@(hObject,eventdata)GUI_xyplotter('request_m2_Callback',hObject,eventdata,guidata(hObject))

??? Error while evaluating uicontrol Callback

Walter Roberson 2011-4-12

Where you have the

t = fread(obj2, 2, 'uint8');

change that to

[t,count,msg] = fread(obj2, 2, 'uint8');

if count < 2

if ischar(msg)

fprintf(1,'request_m2 obj2 read returned only %d bytes, saying that %s\n', count, msg);

else

fprintf(1,'request_m2 obj2 read returned only %d bytes for an unknown reason);

end

return

end

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Answer 13

fremond khoo 2011-4-12

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_7498

在 MATLAB Online 中打开

i am sorry walter..but it seems that the code is unstable..sometimes can sometimes cant..now it shows me this object properties:

It blew up real good!
    ByteOrder = littleEndian
    BytesAvailable = 26
    BytesAvailableFcn = 
    BytesAvailableFcnCount = 48
    BytesAvailableFcnMode = terminator
    BytesToOutput = 0
    ErrorFcn = 
    InputBufferSize = 512
    Name = Serial-COM9
    ObjectVisibility = on
    OutputBufferSize = 512
    OutputEmptyFcn = 
    RecordDetail = compact
    RecordMode = overwrite
    RecordName = record.txt
    RecordStatus = off
    Status = open
    Tag = 
    Timeout = 10
    TimerFcn = 
    TimerPeriod = 1
    TransferStatus = idle
    Type = serial
    UserData = []
    ValuesReceived = 0
    ValuesSent = 35
      SERIAL specific properties:
      BaudRate = 9600
      BreakInterruptFcn = 
      DataBits = 8
      DataTerminalReady = off
      FlowControl = none
      Parity = none
      PinStatus = [1x1 struct]
      PinStatusFcn = 
      Port = COM9
      ReadAsyncMode = continuous
      RequestToSend = off
      StopBits = 1
      Terminator = LF

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Walter Roberson 2011-4-12

Change the find_and_open function as follows and try again:

function obj=ODF_plot(port,wantbaud)

needed_open = true;

obj = instrfind('Type','serial','Port',port);

if isempty(obj);

fprintf(1,'find_and_open: note that instrfind did not find port %s\n', port);

obj = serial(port);

end

curspeed = get(obj,'BaudRate');

if curspeed ~= wantbaud

if strcmpi(get(obj,'Status'),'open');

fclose(obj);

needed_open = false;

fprintf(1,'find_and_open: note that port %s was already open but had the wrong speed, %d\n', port, curspeed)

end

set(obj,'BaudRate',wantbaud);

end

curmode = get(obj,'BytesAvailabelFcnMode');

if ~strcmpi(curmode, 'byte')

if strcmpi(get(obj,'Status'),'open');

fclose(obj);

needed_open = false;

fprintf(1,'find_and_open: note that port %s was already open but had the wrong mode, %s\n', port, curmode)

end

set(obj,'BytesAvailabelFcnMode', 'byte');

end

if ~strcmpi(get(obj,'Status'),'open');

fopen(obj);

if needed_open

fprintf(1,'find_and_open: needed to open port %s\n', port);

end

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Answer 14

fremond khoo 2011-4-12

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_7545

在 MATLAB Online 中打开

Walter..it come out this error:

??? Undefined function or method 'find_and_open' for
input arguments of type 'char'.
Error in ==> GUI_xyplotter>on_m1_Callback at 106
obj1 = find_and_open('COM8',9600);
Error in ==> gui_mainfcn at 96
        feval(varargin{:});
Error in ==> GUI_xyplotter at 16
    gui_mainfcn(gui_State, varargin{:});
Error in ==>
@(hObject,eventdata)GUI_xyplotter('on_m1_Callback',hObject,eventdata,guidata(hObject))
??? Error while evaluating uicontrol Callback

it seems it cannot read the find_and_open function when i executed the buttons..

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Walter Roberson 2011-4-12

Sorry, where I wrote ODF_plot change that to find_and_open .

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Answer 15

fremond khoo 2011-4-13

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_7548

在 MATLAB Online 中打开

yeah..i changed the code into find_and_open and try it out..but the error is something i never seen before..

??? Error using ==> serial.get at 71
There is no 'BytesAvailabelFcnMode' property for serial
port objects.
Error in ==> GUI_xyplotter>find_and_open at 63
curmode = get(obj,'BytesAvailabelFcnMode');
Error in ==> GUI_xyplotter>connect_m1_Callback at 84
obj1 = find_and_open('COM8',9600);
Error in ==> gui_mainfcn at 96
        feval(varargin{:});
Error in ==> GUI_xyplotter at 16
    gui_mainfcn(gui_State, varargin{:});
Error in ==>
@(hObject,eventdata)GUI_xyplotter('connect_m1_Callback',hObject,eventdata,guidata(hObject))
??? Error while evaluating uicontrol Callback

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fremond khoo 2011-4-14

im sorry walter..i did not change to parallel before that..now that i have changed..it has no error..but it state it receive 0 bytes from my motor..

the statement:

request_m1 obj1 read returned only 0 bytes, saying that The specified amount of data was not returned within the Timeout period.

fremond khoo 2011-4-15

it's working walter^^..try again and success!!..deepest gratitude towards walter~~..thanks

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Answer 16

keycamel villegas 2011-4-16

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_7840

hi fremond khoo..did you used a motor driver for your stepper motor?and may i know what are the connections?thank you!!.. im a newbie in matlab..and my thesis project involves the movement of a bipolar stepper motor. :)

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fremond khoo 2011-4-19

im sorry keycamel villegas for the late reply..yup..i use SD02B motor driver(u can search from www.cytron.com)..the connection is fairly easy..just go to cytron and u will know everything^^..cheers..they even provide a manual for you..just go ahead and try it out..my project is about unipolar stepper motor^^

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Answer 17

keycamel villegas 2011-4-19

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_8085

my project involves a bipolar stepper motor and im using L298 motor driver..would it be possible that your code above can be used in our project?

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fremond khoo 2011-4-19

you can try them out..u are using serial port or parallel?

keycamel villegas 2011-4-19

our professor said that our connection would be:

RS232 to serial to parallel converter(using 4 bit shift register) to l298 motor driver connected to bipolar stepper motor,,

would that be possible?or can you suggest other connection for our bipolar stepper motor because i have difficulty analyzing the connections of this components,,

by the way THANK YOU for your reply :)

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Answer 18

keycamel villegas 2011-4-19

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/4059-how-to-control-stepper-motor-speed-via-usb-port#answer_8086

our professor said that our connection would be:

RS232 to serial to parallel converter(using 4 bit shift register) to l298 motor driver connected to bipolar stepper motor,,

would that be possible?or can you suggest other connection for our bipolar stepper motor because i have difficulty analyzing the connections of this components,,

by the way THANK YOU for your reply :)

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keycamel villegas 2011-5-6

can i asked you a question? how uart of a microcontroller communicate with the uart of matlab?.thank you

Walter Roberson 2011-5-6

The program running on the microcontroller uses system-specific methods to cause the microcontroller's UART to send the bytes out.

Please start a new question for these kinds of topics; this question is very long and difficult to follow.

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