MATLAB: Serial port time stamping question.

serialserial porttime stamp

It's been a while since I've worked with MATLAB, so bear with me.

A few timing questions:

1.) What is the best way to timestamp data coming in on a serial port?

2.) What does MATLAB use to timestamp the data? Does using NTP make a difference?

Thank you for the help!

-Adam

Best Answer

Ended up timestamping with a NIDAQ box for high accuracy. MATLAB's not "real-time" enough.

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MATLAB: Error Dialog Box for Serial Communication

Unfortunately the documentation of serial does not explain what happens, if the port cannot be opened. Therefore I guess:

try
  s_port=serial('COM6','BaudRate',115200,'Parity','none', ...
                'DataBits',8,'FlowControl','none');
catch
  errordlg(...)
  return;
end

Or:

s_port = serial('COM6','BaudRate',115200,'Parity','none', ...
                'DataBits',8,'FlowControl','none');
if isempty(s_port)  % or what ever, please simply test this
  errordlg(...)
  return;
end

MATLAB: Add date stamp to time stamp

Here's how I'd do it. Whatever you do don't use outdated datenum and datestr. Stay with datetime and duration arrays.

[h, m, s] = hms(HRV_BB3.Time(end));  %extract hours, minutes and seconds from last time (actually a datetime whose date is wrong)
enddate = datetime(2018,5,21,h,m,s)  %calculate the right datetime
HRV_BB3.DateTime = enddate + [cumsum(-mod(diff(HRV_BB3.Time), hours(24)), 'reverse'); 0];  %calculate difference between consecutive dates, modulo 24h, and add that back

Done!

This assumes of course that days aren't skipped. But since you've lost that information, there's no way to know.

Best Answer

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MATLAB: Error Dialog Box for Serial Communication

MATLAB: Add date stamp to time stamp

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