User`s guide

Remarks
Factory GPIB address setting is 22.
Your computer's GPIB interface card has its own address. Be sure to avoid
using the computer's address for any instrument on the interface bus.
The GPIB address is stored in non-volatile memory, and does not change
when power has been off, after a Factory Reset (*RST command), or after
an Instrument Preset (SYSTem:PRESet command).