Standard Notation This section uses several forms of notation that have specific meaning.

Command Mnemonics

Many commands have both a long and a short form, and you must use either one or the other (SCPI does not accept a combination of the two). Consider the FREQuency command, for example. The short form is FREQ and the long form is FREQUENCY (this notation style is a shorthand to document both the long and short form of commands). SCPI is not case sensitive, so fREquEnCy is just as valid as FREQUENCY, but FREQ and FREQUENCY are the only valid forms of the FREQuency command.

Angle Brackets

Angle brackets indicate that the word or words enclosed represent something other than themselves. For example, <new line> represents the ASCII character with the decimal value 10. Similarly, C^END>means that EOI is asserted on the HP-IB interface. Words in angle brackets have much more rigidly defined meaning than words used in ordinary text. For example, this section uses the word “message” to talk about messages generally. But the bracketed words <program message> indicate a precisely defined element of SCPI.

If you need them, you can find the exact definitions of words such as <program message> in a syntax diagram.

How to Use Examples It is important to understand that programming with SCPI actually requires knowledge of two languages. You must know

the programming language of your controller (BASIC, C, Pascal) as well as the language of your instrument (SCPI). The semantic requirements of your controller’s language determine how the SCPI commands and responses are handled in your application.

Command Examples

Command examples look like this:

:FREQuency:CW?

This example tells you to put the string :FREQuency :CW? in the output statement appropriate to your application programming language. If you encounter problems, study the details of how the output statement handles message terminators such as <new line>. If you are using simple OUTPUT statements in HP BASIC, this is taken care of for you. In HP BASIC, you type:

OUTPUT Source; ” : FREQuency : CW?”

Command examples do not show message terminators because they are used at the end of every program message. “Details of

1-64 Getting Started Programming