Boonton 9240 RF Voltmeter - Manual (Page 53)

Boonton 9240 Series RF Voltmeter
suffix is not present, the default channel is assumed. For example, SENSe or SENSe1 defines operation affecting the
instrument’s “Channel 1” measurement path, while SENSe2 commands will apply to channel 2.
5.3.4 Colon Keyword Separators
The colon (“:”) character is used similar to the way a slash or backslash is used in a filesystem. Prefixing a command string
with a colon resets parsing at the root command level, and a colon must separate each keyword in the command. Beginning a
new line always resets parsing to the root level, so the leading colon is optional if the command is the first command on a
line.
5.3.5 Command Arguments and Queries
Many commands require arguments. In this case, the entire command string is sent, followed by the argument. A space is
used to separate the command from the argument. For example, “SENSe:CORRection:DCYCle 25.0” sets duty cycle
correction to a value of 25.0. Arguments may be numeric, or alphanumeric. If a command requires more than one numeric
argument, the arguments must be sent as a comma delimited list.
To read the current value of a particular parameter, the Query Form of its command may be used. A command query is
formed by appending a question-mark (“?”) suffix to the command instead of an argument list. There should not be any
whitespace between the command and the suffix. For example, “SENSe:CORRection:DCYCle?” queries the duty cycle
correction parameter, and causes the instrument to return its current value.
5.3.6 Semicolon Command Separators
The semicolon (“;”) character is used to separate multiple commands on a single line. However, the parsing path is affected
when more than one command is combined on a line. As noted previously, the first command of a line is always referenced
to the root level whether or not the command is prefixed by a colon. However, for the second and succeeding commands, the
parsing level is NOT reset to the root level, but rather referenced from the current node. This allows the parser to remain at
the current node, and execute other commands from that node without resending the entire node string. For example, the
following multi-command strings are equivalent:
:CALCulate:LIMit:LOWer -10.0; CALCulate:LIMit:UPPer 13.0; (two full-path commands)
:CALCulate:LIMit:LOWer -10.0; UPPer 13.0; ( second command referenced to CORRection node)
CALCulate:LIMit:LOWer -10.0; UPPer 13.0; (leading colon omitted from first command)
If a command does not belong to the same subsystem as the preceding command on the same line, then its full path must be
specified, including the colon prefix.
5.3.7 Command Terminators
All SCPI command strings transmitted to the instrument must be terminated. For commands sent via the GPIB bus, any
character with the IEEE488 EOI (End-Or-Identify) control line asserted may be used as a terminator. This may be the last
letter of the command, query or argument. Optionally, a CR (ASCII 13) and/or LF (ASCII 10) may be included.
For commands sent via the RS-232 interface a CR and/or LF must be included to match the desired protocol.
When the terminating condition is met, the SCPI path is first reset to the root level, and the received message is then passed
to the SCPI parser for evaluation.
5.3.8 9240 Series SCPI Implementation
The SCPI Model of the 9240 provides a single or dual SENSe sub-system to handle probe input and a matching single or dual
CALCulate sub-system to process the data obtained from the probes into useful results. The CALibration sub-system is used
Remote Operation
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