Hello!

I'm an absolute beginner on GPIB-commands, but I want to write a program to write down measurements of an digital electrometer with an IEEE488-interface.
The electrometer is Keithley 6514 with a National Instruments GPIB-USB-HS-adapter.

I installed all the drivers/programs provided by NI for this adapter and the "Measurement and Automation Explorer" was able to detect the adapter and electrometer!
Then I followed the instruction to test the connection with the "Interactive control", sending traditional NI-488.2-Calls:
ibdev 0 16 0 10 1 0
ibclr
ibwrt "*IDN?"
ibrd 100
ibonl 0

They do what they supposed to do, writing and reading the identification-information of the electrometer...
But when I try any other command to actually read the measured data (and even without a device connected to the electrometer, there should be plenty of ~0, right?) every time I get an error or another.
Just using ibrd again leads to timeout-errors EABO, while the electrometer's display show Error 420.
I already tried to combine it with ibloc or using ibrda etc, getting error-codes like 411, 410, 210...

 Do I need another String to send to get the data?
Or am I using it totally wrong^^
I plan to connect to it with a C++-program (embarcadero/borland's version) later on...
Are there problems using the C-commands listed in the help-file outside of microsoft's C++?

Regards,
Julian