Thread: Basic MATLAB script to connect to Agilent Scope

I write a lot of scripts to talk to Agilent Infiniium Oscilloscopes. I find that the primary 'Acquisition' part of the scripts is all about the same. Here is what I tend to use, as a minimum, to set up the scope, capture data, and move it into MATLAB. It's not perfect, or maybe the best, but I think it's understandable. There may be errors, since I cut-and-pasted from a much larger script. Feel free to use it as you please.

function SetupandRun(visaAddress, Depth, Sample_Rate, Sig_Ch_Num)
% Connect to the instrument and set the buffer size and instrument timeout
inst = visa('agilent', visaAddress);

inst.InputBufferSize = 10000000; % This may need to be adjusted (depth * 2) + 1 should be enough
inst.Timeout = 10;
inst.ByteOrder = 'littleEndian';

fopen(inst);

Sig_Ch = ;

% Set the initial instrument parameters
fprintf(inst, '*RST');
fprintf(inst, ':stop;:cdis');
fprintf(inst, '*OPC?'); Junk = str2double(fscanf(inst));
fprintf(inst, );
fprintf(inst, '*OPC?'); Junk = str2double(fscanf(inst));
fprintf(inst, );
fprintf(inst, );
fprintf(inst, ':TRIGGER:EDGE:SLOPE POSITIVE');
fprintf(inst, );
fprintf(inst, ':ACQUIRE:MODE RTIME');
fprintf(inst, );
fprintf(inst, '*OPC?'); Junk = str2double(fscanf(inst));

% Get some data.
fwrite(inst, '*cls');
fwrite(inst, ':single');
% Wait for a trigger
ter = 0;
while(ter ~= 1)
fwrite(inst, ':ter?');
stringTer = fscanf(inst, '%s');
ter = str2double(stringTer);
end

% Now unload the ScopeData
fprintf(inst, ['WAV:SOURCE ', Sig_Ch);
fprintf(inst, 'WAV:FORMAT WORD');
fprintf(inst, 'WAVEFORM:BYTEORDER LSBFirst');
preambleBlock = query(inst,':WAVEFORM:PREAMBLE?');
fprintf(inst, '*OPC?'); Junk = str2double(fscanf(inst));
fprintf(inst,':WAV:DATA?');
ScopeData.RawData = binblockread(inst,'int16');
Junk = fread(inst,1,'schar'); % Read the EOF character
maxVal = 2^16;
preambleBlock = regexp(preambleBlock,',','split');
ScopeData.Format = str2double(preambleBlock{1}); % This should be 1, since we're specifying INT16 output
ScopeData.Type = str2double(preambleBlock{2});
ScopeData.Points = str2double(preambleBlock{3});
ScopeData.Count = str2double(preambleBlock{4}); % This is always 1
ScopeData.XIncrement = str2double(preambleBlock{5}); % in Time
ScopeData.XOrigin = str2double(preambleBlock{6}); % in Time
ScopeData.XReference = str2double(preambleBlock{7});
ScopeData.YIncrement = str2double(preambleBlock{8}); % Voltage
ScopeData.YOrigin = str2double(preambleBlock{9});
ScopeData.YReference = str2double(preambleBlock{10});
ScopeData.VoltsPerDiv = (maxVal * ScopeData.YIncrement /8); % V
ScopeData.Offset = ((maxVal/2 - ScopeData.YReference) * ScopeData.YIncrement + ScopeData.YOrigin); % V
ScopeData.SecPerDiv = ScopeData.Points * ScopeData.XIncrement/10 ; % seconds
ScopeData.Delay = ((ScopeData.Points/2 - ScopeData.XReference) * ScopeData.XIncrement + ScopeData.XOrigin); % seconds

% Scale the ScopeData
ScopeData.Time = (ScopeData.XIncrement.(1:length(ScopeData.RawData))) - ScopeData.XIncrement;
ScopeData.Volt = (ScopeData.RawData - ScopeData.YReference) . ScopeData.YIncrement + ScopeData.YOrigin;

fclose(inst);
delete(inst);

@algoss
Why do you use sometimes fprintf, sometimes fwrite. Why sometimes query aswell as scanf and binblockread?

It's programming style, or maybe lack thereof. I pulled some pieces of the code from different places, and wasn't careful about how I pulled them together.

IIRC, there are also issues with building a formatted string on the fly.

Al