HP 16500C Programmer's Manual page 90

Message Communication and System Functions
Syntax Overview
Suffix Unit The suffix units that the instrument will accept are shown
in table 6-2.
Table 6-2 <suffix unit>
Suffix
V
S
Example To specify 3 ns, you might enter
6–10
Referenced Unit
Volt
Second
or
3NS 3E-9 S
in your program.