What is your picoammeter address and what is your GPIB-USB address? These need to have different addresses, and you need to make sure that your program uses the correct address for the correct function. I belive that during initialization the input should be the address of the GPIB-USB, and during Write the address should be the address of the picoammeter. Does that make sense? If you use the same address for both initialization and for read/write, you will probably get an error.
My picoammeter is at GPIB0-16 and my GPIB-USB is at GPIB0-0
When my testbench worked; I was initializing and writing on the picoammeter's adress
It worked perfectly two day and didn't the third when I restarted my testbench
My Matlab code to initialize :
%MATLAB_GPIB_LOG Code for initialising the Picoammeter
% Find a GPIB object.
obj1 = instrfind('Type', 'gpib', 'BoardIndex', 0, 'PrimaryAddress', 16, 'Tag', '');
% Create the GPIB object if it does not exist
% otherwise use the object that was found.
if isempty(obj1)
obj1 = gpib('ni', 0, 16);
else
fclose(obj1);
obj1 = obj1(1);
end;
% Connect to instrument object, obj1.
fopen(obj1);
% Communicating with instrument object, obj1.
query(obj1, 'DISP:ENAB OFF');
query(obj1, '*IDN?');
query(obj1, '*RST');
query(obj1, 'SYST:ZCH ON');
query(obj1, 'RANG 2e-9');
query(obj1, 'INIT');
query(obj1, 'SYST:ZCOR:ACQ');
query(obj1, 'SYST:ZCOR ON');
query(obj1, 'RANG:AUTO ON');
query(obj1, 'SYST:ZCH OFF');
query(obj1, 'FORM:ELEM READ');
query(obj1, 'READ?');
query(obj1, 'FORM:ELEM READ');
