iterate through multiple serial ports, one after another (not simultaneously)

Question

avram alter 2019-10-3

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/483491-iterate-through-multiple-serial-ports-one-after-another-not-simultaneously

评论： avram alter 2021-5-3

I have a program that utilizes incoming serial data to do a strcmp with data stored in excel. the string initially comes in looking like this:

Reader(n): 'String'

my code is set up to find the n, and then compare the serial string to the string stored in the Nth column of an excel spreadsheet. A bool value of 1 from this operation will change the Nth panel in a GUI to green, while a bool value of 0 will change the Nth panel to red.

At the moment, my code only iterates from n = 1:2. these are the n values coming in from COM3. I want to use 3 more COM ports, each one carrying n = 3:4, n = 5:6, and n = 7:8. However, I am unsure of how to initialize the ports to be read one after another, no simultaneously. this is my main function:

delete(instrfind('Port', 'COM3')); % removes possibility for 'Port not available' error
tag = serial('COM3'); %initializes the port to be used
fopen(tag); %opens th eport
BOX = char(zeros(2,14)); % matrix to be populated with incoming serial data
TrueValueData = 'C:\RfidChipTrueValues.xlsx'; 
% location of stored master tags
[~,~,TrueValMat] = xlsread(TrueValueData); % reads our excel file into the proper format
% Creates matrix filled with the correct values
% indexed by box, which is the first row
% all proceeding rows are the master value
for i=1:inf
    for n = 1:2
        if i>10 % positive reading
            readData = fscanf(tag);
            if length(readData)>12
                BOX(str2double(readData(8)),1:14)= readData(11:24); 
                if strcmp(TrueValMat{2,n}, BOX(n,:)) %cannot sub-index to CELL types normally, must use this method
                    set(handles.uipanels(n), 'BackgroundColor', 'g');
                else
                    set(handles.uipanels(n), 'BackgroundColor', 'r');
                end
                drawnow % allows GUI to update the appearance whenever the loop completes.
                if strcmp(TrueValMat{2,1}, BOX(1,:))...
                        && strcmp(TrueValMat{2,2}, BOX(2,:)) == 1
                    set(handles.pushbutton5, 'enable', 'on');
                end
            end
        end
    end
end

the GUI at this point works well, with only minor things to be ironed out in the future. the colors change correctly, etc.

This is all for only a single com port. how do I make this work with 3 additional ports?

I know about bytesavailablefcn, but I have no clues how to use it, even after hours spent reading about it, watching videos, etc. obviously I am open to using anything that works, but it will have to really be explained to me.

Thanks so much

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Answer 1

Walter Roberson 2019-10-3

1
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/483491-iterate-through-multiple-serial-ports-one-after-another-not-simultaneously#answer_394722

在 MATLAB Online 中打开

portlist = {'COM3', 'COM4', 'COM7', 'COM12'};
nport = length(portlist);
tags = cell{1, nport};
cleanups = cell{1, nport};
for portidx = 1 : nport
    delete(instrfind('Port', portlist{portidx})); % removes possibility for 'Port not available' error
    tags{portidx} = serial(portlist{portidx}); %initializes the port to be used
    fopen(tag); %opens th eport
    cleanups{portidx} = onCleanup(@() fclose(portlist{portidx}));
end
BOX = char(zeros(2,14)); % matrix to be populated with incoming serial data
TrueValueData = 'C:\RfidChipTrueValues.xlsx'; 
% location of stored master tags
[~,~,TrueValMat] = xlsread(TrueValueData); % reads our excel file into the proper format
% Creates matrix filled with the correct values
% indexed by box, which is the first row
% all proceeding rows are the master value
for i=1:inf
    for portidx = 1 : nport
        nbase = portidx * 2 - 1;
        for n = nbase:nbase+1
            if i>10 % positive reading
                readData = fscanf(tags{portidx});;
                if length(readData)>12
                    BOX(str2double(readData(8)),1:14)= readData(11:24); 
                    if strcmp(TrueValMat{2,n}, BOX(n,:)) %cannot sub-index to CELL types normally, must use this method
                        set(handles.uipanels(n), 'BackgroundColor', 'g');
                    else
                        set(handles.uipanels(n), 'BackgroundColor', 'r');
                    end
                    drawnow % allows GUI to update the appearance whenever the loop completes.
                    if strcmp(TrueValMat{2,1}, BOX(1,:))...
                            && strcmp(TrueValMat{2,2}, BOX(2,:)) == 1
                        set(handles.pushbutton5, 'enable', 'on');
                    end
                end
            end
        end
    end
end

If you want something different to be done for the different ports, then you can test the portidx value.

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avram alter 2019-10-29

编辑：avram alter 2019-10-29

在 MATLAB Online 中打开

its been a bit of a hectic month, I apologize for taking so long to get back to you. I get an error

Invalid syntax for calling function 'cell' on the path. Use a valid syntax or
explicitly initialize 'cell' to make it a variable.

and I am not sure what to do from here.

this is the relevant code that I copied from your answer:

% --- Outputs from this function are returned to the command line.
function varargout = WorkingGUI3_OutputFcn(hObject, eventdata, handles)
%delete(instrfind('Port', 'COM3')); % removes possibility for 'Port not available' error
%tag = serial('COM3'); %initializes the port to be used
%fopen(tag); %opens the port
portlist = {'COM3', 'COM4'}
nport = length(portlist);
tags = cell{1, nport};
cleanups = cell{1, nport};
for portidx = 1 : nport
    delete(instrfind('Port', portlist{portidx}));  % removes possibility for 'Port not available' error
    tags{portidx} = serial(portlist{portidx}); %initializes the port to be used
    cleanups{portidx} = onCleanup(@() fclose(portlist{portidx}));
end
BOX = char(zeros(2,14)); % matrix to be populated with incoming serial data
TrueValueData = 'C:\RfidChipTrueValues.xlsx';
% location of stored master tags
[~,~,TrueValMat] = xlsread(TrueValueData); % reads our excel file into the proper format
% Creates matrix filled with the correct values
% indexed by box, which is the first row
% all proceeding rows are the master value
for i=1:inf
    pause(0.01)
    %     for n = 1:2
    for portidx = 1 : nport
        nbase = portidx * 2 - 1;
        for n = nbase:nbase+1
            if i>10 % positive reading
                %             readData = fscanf(tag);
                readData = fscanf(tags{portidx});
                if length(readData)>12
                    BOX(str2double(readData(8)),1:14)= readData(11:24);
                    if strcmp(TrueValMat{2,n}, BOX(n,:)) %cannot sub-index to CELL types normally, must use this method
                        set(handles.uipanels(n), 'BackgroundColor', 'g');
                    else
                        set(handles.uipanels(n), 'BackgroundColor', 'r');
                    end
                    drawnow % allows GUI to update the appearance whenever the loop completes.
                    if strcmp(TrueValMat{2,1}, BOX(1,:))...
                            && strcmp(TrueValMat{2,2}, BOX(2,:)) == 1
                        set(handles.pushbutton5, 'enable', 'on');
                    end
                end
            end
        end
    end
end
% varargout  cell array for returning output args (see VARARGOUT);
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% Get default command line output from handles structure
varargout{1} = handles.output;

thanks again for the help

avram alter 2019-10-29

在 MATLAB Online 中打开

Error using fopen
First input must be a file name or a file identifier.
Error in WorkingGUI3>WorkingGUI3_OutputFcn (line 78)
    fopen(tags); %opens th eport
Error in gui_mainfcn (line 264)
        feval(gui_State.gui_OutputFcn, gui_hFigure, [], gui_Handles);
Error in WorkingGUI3 (line 42)
    gui_mainfcn(gui_State, varargin{:});
    

I corrected the other error as well, here is code now:

% --- Outputs from this function are returned to the command line.
function varargout = WorkingGUI3_OutputFcn(hObject, eventdata, handles)
% delete(instrfind('Port', 'COM3')); % removes possibility for 'Port not available' error
% tag = serial('COM3'); %initializes the port to be used
% fopen(tag); %opens th eport
portlist = {'COM3', 'COM4'};
nport = length(portlist);
tags = cell(1, nport);
cleanups = cell(1, nport);
for portidx = 1 : nport
    delete(instrfind('Port', portlist{portidx})); % removes possibility for 'Port not available' error
    tags{portidx} = serial(portlist{portidx}); %initializes the port to be used
    fopen(tags); %opens th eport
    cleanups{portidx} = onCleanup(@() fclose(portlist{portidx}));
end
BOX = char(zeros(2,14)); % matrix to be populated with incoming serial data
TrueValueData = 'C:\Users\Administrator\Dropbox (esberlab)\esberlab Team Folder\Matlab\RFID chip reader\RfidChipData\RfidChipTrueValues.xlsx';
% location of stored master tags
[~,~,TrueValMat] = xlsread(TrueValueData); % reads our excel file into the proper format
% Creates matrix filled with the correct values
% indexed by box, which is the first row
% all proceeding rows are the master value
for i=1:inf
    pause(0.01)
    %     for n = 1:2
    for portidx = 1 : nport
        nbase = portidx * 2 - 1;
        for n = nbase:nbase+1
            if i>10 % positive reading
                %             readData = fscanf(tag);
                readData = fscanf(tags{portidx});
                if length(readData)>12
                    BOX(str2double(readData(8)),1:14)= readData(11:24);
                    if strcmp(TrueValMat{2,n}, BOX(n,:)) %cannot sub-index to CELL types normally, must use this method
                        set(handles.uipanels(n), 'BackgroundColor', 'g');
                    else
                        set(handles.uipanels(n), 'BackgroundColor', 'r');
                    end
                    drawnow % allows GUI to update the appearance whenever the loop completes.
                    if strcmp(TrueValMat{2,1}, BOX(1,:))...
                            && strcmp(TrueValMat{2,2}, BOX(2,:)) == 1
                        set(handles.pushbutton5, 'enable', 'on');
                    end
                end
            end
        end
    end
end
% varargout  cell array for returning output args (see VARARGOUT);
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% Get default command line output from handles structure
varargout{1} = handles.output;

avram alter 2021-4-29

在 MATLAB Online 中打开

Hello! It has been 2 years, but the code is slowly coming together. I am now working with other people, and I find myself needing to explain certain parts of the code that I did not write. over the years you have been an incredible help to me, so I have one last question for you. what is the purpose of this bit?

portlist = {'COM3', 'COM4'};
nport = length(portlist);
tags = cell(1, nport);
cleanups = cell(1, nport);
for portidx = 1 : nport
    delete(instrfind('Port', portlist{portidx})); % removes possibility for 'Port not available' error
    tags{portidx} = serial(portlist{portidx}); %initializes the port to be used
    fopen(tags); %opens th eport
    cleanups{portidx} = onCleanup(@() fclose(portlist{portidx}));
end

would you be able to explain line by line, what is being done here? similarly,

for i=1:inf
    pause(0.01)
    %     for n = 1:2
    for portidx = 1 : nport
        nbase = portidx * 2 - 1;
        for n = nbase:nbase+1
        end
        

I cannot figure out what is being done here. could you explain this as well?

thank you so much for your time, and thank you for all the help you have given me over the years.

Walter Roberson 2021-5-3

I do not explain code "line by line". When someone asks me to explain code "line by line", that means that I have to write a textbook on programming principles, and then a second textbook about programming in MATLAB, as I have to assume that everything about the code is unknown to them.

The first code loops through a fixed set of port names. It checks to see whether the port is already in use, and if so it tells MATLAB to get rid of the existing connection. Then it creates a serial port interface to the port. Finally, it creates an onCleanup object that closes the port when the cleanups variable is destroyed, such as if the user does a clear all or if the user returns from the function that opens the ports without saving the cleanup objects somewhere.

The second code loops forever reading from each port in turn. The first port uses n = 1:2, the second port uses n = 3:4, and so on. So port #K uses n = (2*K-1):(2*K)

avram alter 2021-5-3

I do appreciate the explanation you've given me here, so thank you very much.

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Answer 2

avram alter 2019-10-29

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/483491-iterate-through-multiple-serial-ports-one-after-another-not-simultaneously#answer_398816

在 MATLAB Online 中打开

readers 1 and 2 (both on com3) work perfectly now. however, when a tag is held up to the third reader (on Com4), I get this error:

Index exceeds the number of array elements (2).
Error in WorkingGUI3>WorkingGUI3_OutputFcn (line 103)
                        set(handles.uipanels(n), 'BackgroundColor', 'r');
Error in gui_mainfcn (line 264)
        feval(gui_State.gui_OutputFcn, gui_hFigure, [], gui_Handles);
Error in WorkingGUI3 (line 42)
    gui_mainfcn(gui_State, varargin{:});

this is the code I have now:

% --- Outputs from this function are returned to the command line.
function varargout = WorkingGUI3_OutputFcn(hObject, eventdata, handles)
% delete(instrfind('Port', 'COM3')); % removes possibility for 'Port not available' error
% tag = serial('COM3'); %initializes the port to be used
% fopen(tag); %opens th eport
portlist = {'COM3', 'COM4'};
nport = length(portlist);
tags = cell(1, nport);
cleanups = cell(1, nport);
for portidx = 1 : nport
    delete(instrfind('Port', portlist{portidx})); % removes possibility for 'Port not available' error
    tags{portidx} = serial(portlist{portidx}); %initializes the port to be used
    fopen(tags{portidx}); %opens th eport
    cleanups{portidx} = onCleanup(@() fclose(portlist{portidx}));
end
BOX = char(zeros(3,14)); % matrix to be populated with incoming serial data
TrueValueData = 'C:\Users\Administrator\Dropbox (esberlab)\esberlab Team Folder\Matlab\RFID chip reader\RfidChipData\RfidChipTrueValues.xlsx';
% location of stored master tags
[~,~,TrueValMat] = xlsread(TrueValueData); % reads our excel file into the proper format
% Creates matrix filled with the correct values
% indexed by box, which is the first row
% all proceeding rows are the master value
for i=1:inf
    pause(0.01)
    %     for n = 1:2
    for portidx = 1 : nport
        nbase = portidx * 2 - 1;
        for n = nbase:nbase+1
            if i>10 % positive reading
                %             readData = fscanf(tag);
                readData = fscanf(tags{portidx});
                if length(readData)>12
                    BOX(str2double(readData(8)),1:14)= readData(11:24);
                    if strcmp(TrueValMat{2,n}, BOX(n,:)) %cannot sub-index to CELL types normally, must use this method
                        set(handles.uipanels(n), 'BackgroundColor', 'g');
                    else
                        set(handles.uipanels(n), 'BackgroundColor', 'r');
                    end
                    drawnow % allows GUI to update the appearance whenever the loop completes.
                    if strcmp(TrueValMat{2,1}, BOX(1,:))...
                            && strcmp(TrueValMat{2,2}, BOX(2,:)) == 1
                        set(handles.pushbutton5, 'enable', 'on');
                    end
                end
            end
        end
    end
end
% varargout  cell array for returning output args (see VARARGOUT);
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% Get default command line output from handles structure
varargout{1} = handles.output;

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Walter Roberson 2019-10-29

编辑：Walter Roberson 2019-10-29

在 MATLAB Online 中打开

Note that you do not need the "== 1" part.

if      strcmp(TrueValMat{2,1}, BOX(1,:)) ...
     && strcmp(TrueValMat{2,2}, BOX(2,:)) ...
     && strcmp(TrueValMat{3,1}, BOX(3, :))
     set(handles.pushbutton5, 'enable', 'on');
 end
                    

avram alter 2019-10-29

thanks for all the help

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iterate through multiple serial ports, one after another (not simultaneously)

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iterate through multiple serial ports, one after another (not simultaneously)

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