User`s guide

Command Separators
A colon ( : ) is used to separate a command keyword from a lower-level
keyword. You must insert a blank space to separate a parameter from a
command keyword. If a command requires more than one parameter, you
must separate adjacent parameters using a comma as shown below:
CONF:VOLT:DC 10,0.003
A semicolon ( ; ) is used to separate commands within the same subsystem,
and can also minimize typing. For example, sending the following command
string:
TRIG:SOUR EXT; COUNT 10
... is the same as sending the following two commands:
TRIG:SOUR EXT
TRIG:COUNT 10
Use a colon and a semicolon to link commands from different subsystems. For
example, in the following command string, an error is generated if you do not
use both the colon and semicolon:
TRIG:COUN MIN;:SAMP:COUN MIN