Keysight Technologies 3458A Guide D'utilisation page 227

Multiple commands
Multiple commands, separated by semicolons, may be sent in one command
string. For example, the following command string contains three multimeter
commands.
OUTPUT 722; "TRIG HOLD;DCV 3;NPLC 10"
Parameters
Numbers specified as command parameters can be either integer, floating-point,
or exponential in format. parameters in floating-point format are rounded to the
nearest integer if the command requires an integer. For example, "SUB 2.49" is
rounded down to "SUB 2" and "SUB 2.5" is rounded up to "SUB 3".
Defaulting parameters
You can default a parameter by omitting it or replacing it with -1 (minus 1). For
example, to specify 10 for the first parameter and default the second parameter
send:
OUTPUT 722;"ACV 10"
or
OUTPUT 722;"ACV 10,-1"
From remote only, you can use two commas to indicate a default value. For
example, to specify 10 for the first parameter and default the second parameter,
send:
OUTPUT 722;"ACV 10,,"
To default the first parameter (which selects autorange in this example) and
specify .01 for the second parameter, send:
OUTPUT 722; "ACV,,.01"
Keysight 3458A User's Guide
Command Reference 6
227