How to use parallel background computing for triggering a oscilloscope measurement device (VISA API, IVI-C) from a matlab GUI? (error "Cannot parse adapters.config file")

I want to trigger and collect data of my Tektronix DPO2004B Oscilloscope (Connected via USB and VISA API using a IVI-C Driver) from a Matlab GUI/App. For communication with the Oscilloscope I use the Quick-Control Oscilloscope instrument functionality (https://de.mathworks.com/help/instrument/oscilloscope.html)

If i use the function getDataFromOszilloscope() (see code below) it works fine, but the whole process of data collection takes about 7 seconds. When i call this function from a Matlab app, the execution will be blocked for a long time and other tasks can't be handled during this time. Therefore i want to call this function in a parallel background pool. When i use f = parfeval(backgroundPool, @getDataFromOszilloscope,1); the following error occurs during the connection process inside oscilloscope().

Errormessage: Identifier "instrument:oscilloscope:failedToParseConfigFile"; "Cannot parse adapters.config file".

I guess the problem could be, that the backgroundPool uses all my Workers (6x) on the machine and this doesn't work for this kind of device object, but i have no experience with parallel computing and scheduling. The function can be called when i use the parfeval(@getDataFromOszilloscope,1) without a backgroundPool and one Worker, but it still blocks the rest of my functionality because its not fully separated. I made a solution with the batch() function but it takes a lot of time to start the parallel pool every time i trigger the data acquisition.

Is there any way to get data from this oscilloscope without blocking the execution of other code inside the GUI?

%% Get data from Oszilloscope
p = backgroundPool;  %Create backgroundPool
counter = 1;
numOfMeasurements = 4;
f(1:numOfMeasurements) = parallel.FevalFuture; %preallocate Future Object
%% Read specified number of measurements
while true
    %Exit while loop if all measurements are collected in Background
    if sum(ismember({f.State},'finished')) == numOfMeasurements 
        out = fetchOutputs(f); %get data from background execution (Matlab throws error here but Problem occurs during parfeval)
        break;
    end
    %Call Oszi at first iteration and after finishing calculation in background
    if counter == 1 || strcmp(f(counter-1).State,'finished') 
        disp('Calling getData')
        %Trigger oscilloscope for data collection in background
        f(counter) =  parfeval(p, @getDataFromOszilloscope,1);  %Error
        counter = counter+1;
    end
    disp(f(counter-1).State) %Output to check status of background calculation

    % OTHER CODE FOR FURTHER EXECUTION IN APP WILL FOLLOW HERE
end
disp('END')

%% Function for connecting to oscilloscope via installed IVI instrument driver (Uses VISA API)
% Error occurs during connection with the Oscilloscope
function data = getDataFromOszilloscope() 
pause(0.1)
VisaAddress = 'USB0::0x0699::0x039B::C020206::0::INSTR';
IVI_Driver = 'Tkdpo2k3k4k';
myScope =   oscilloscope(VisaAddress,IVI_Driver);  %THE ERROR OCCURS HERE WHEN EXECUTED IN BACKGROUND!
data = readWaveform(myScope,'acquisition', true); %Get Data from Oscilloscope 
end

Further information:

Hardware + Driver:

• Oscilloscope Tektronix DPO2004B
• - IVI-C Driver Tkdpo2k3k4k v1.5 https://www.tek.com/en/support/software/driver/dpo2000-mso2000-dpo3000-and-dpo4000-mso3000-and-mso4000-mdo3000-and

Used Software:

• Matlab R2023b
• Matlab Instrument Toolbox
• Instrument Control Toolbox Support Package for National Instruments VISA and ICP Interfaces https://de.mathworks.com/help/instrument/install-the-national-instruments-visa-and-icp-interfaces-support-package.html
• NI-VISA software packages (installed with the VISA instrument control toolbox).

Answer 1

[Harald]

Hi,

only a limited set of functions is supported in backgroundPool. If a function is supported, this is listed in the "Extended Capabilities" section of the documentation.

batch will always start and shut down workers and is therefore not a good idea for this application.

I would expect things to work in a "regular" parpool, i.e.

p = parpool("Processes", 1);

Best wishes,

Harald

[Florian Zacherl]

Hi Harald, sorry for the late response and thank you very much for your help. I could solve my problem with parpool("Processes",1).