Thanks,I already tried this driver, but it didn't work. First I got an error 1223 (Equipment identification inquiry missed). After I had changed the ID inquiry in the driver in the "HP 54720A initialize.vi" on hp 54720D, I got with the call of the "HP 54720A example.vi", which is contained in the driver, an error 1300 (device-specific error). There must be a difference between 54720A and D. I have already asked Agilent for information but I'm still waiting for answer. More importantly for me would be a driver for lv 5.0.1, since my predecessor already developed some programs with this version and so my boss would like to change the version only reluctantly