SCPI Command Terminators
A command string sent to the instrument must terminate with a <new line> (<NL>) character (ASCII decimal 10).
The IEEE-488 EOI (End-Or-Identify) message is interpreted as a <NL> character and can be used to terminate a
command string in place of a <NL> character. A <carriage return> followed by a <NL> is also accepted. Command
string termination will always reset the current SCPI command path to the root level.
For every SCPI message that includes a query and is sent to the instrument, the
instrument terminates the returned response with a <NL> or line-feed character (EOI).
For example, if R? is sent, the response is terminated with a <NL> after the block of data
that is returned. If a SCPI message includes multiple queries separated by semicolons (for
example "ROUTe:TERMinals?;R?"), the returned response is again terminated by a <NL>
after the response to the last query. In either case, the program must read this <NL> in
the response before another command is sent to the instrument or an error will occur.
IEEE-488.2 Common Commands
The IEEE-488.2 standard defines a set of common commands that perform functions such as reset, self-test and
status operations. Common commands always begin with an asterisk (* ), are three characters in length and may
include one or more parameters. The command keyword is separated from the first parameter by a blank space. Use a
semicolon (; ) to separate multiple commands as shown below:
*RST; *CLS; *ESE 32; *OPC?
SCPI Parameter Types
The SCPI language defines several data formats to be used in program messages and response messages.
Numeric Parameters
Commands that require numeric parameters will accept all commonly used decimal representations of numbers
including optional signs, decimal points, and scientific notation. Special values for numeric parameters such as MIN,
MAX and DEF are also accepted. You can also send engineering unit suffixes with numeric parameters (e.g., M, k, m or
u). If a command accepts only certain specific values, the instrument will automatically round the input numeric
parameters to the accepted values. The following command requires a numeric parameter for the range value:
VOLTage:DC:RANGe {<range>|MIN|MAX|DEF}
Because the SCPI parser is case-insensitive, there is some confusion over the letter "M"
(or "m"). For your convenience, the instrument interprets "mV" (or "MV") as millivolts,
but "MHZ" (or "mhz") as megahertz. Likewise "MΩ" (or "mΩ") is interpreted as megΩ.
You can use the prefix "MA" for mega. For example, "MAV" is interpreted as megavolts.
Discrete Parameters
Discrete parameters are used to program settings that have a limited number of values (like IMMediate, EXTernal or
BUS). They have a short form and a long form just like command keywords. You can mix upper- and lower-case letters.
Query responses will always return the short form in all upper-case letters. The following example requires a discrete
parameters for the temperature units:
UNIT:TEMPerature{C|F|K}
Agilent Truevolt Series DMM Operating and Service Guide 103
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