HP 1650B, Руководство программиста, Страница: 20 / 346

White Space
Instruction Parameters
Header Types
When you look up a query in this programming reference, you’ll a
paragraph labeled “Returned Format” under the one labeled “Query
Syntax” The syntax definition by “Returned format” will always show the
instruction header in square brackets,
like
What this
really means is that the text between the brackets is optional, but it’s also a
quick way to see what the header looks like.
White space is used to separate the instruction header from the
instruction parameters. If the instruction does not use any parameters,
you do not need to include any white space. White space is defined as one
or more spaces. ASCII defines a space to be character 32 (in decimal).
Tabs can used only if your controller first converts them to space
characters before sending the string to the instrument.
Instruction parameters are used to clarify the meaning of the command or
query. They provide necessary data, such as whether a function should be
on or off, which waveform is to be displayed, or which pattern is to be
looked for. Each instruction’s syntax definition shows the parameters, as
well as the values they accept. This chapter’s “Parameter Syntax Rules”
section has all of the general rules about acceptable values.
When an instruction has more than one parameter they are separated by
commas
You are allowed to include spaces around the commas.
There are three types of headers: Simple Command; Compound
Command; and Common Command.
Simple Command Header. Simple command headers contain a single
keyword. START and STOP are examples of simple command headers
typically used in this instrument. The syntax
<function <terminator
When parameters (indicated by c data must be included with the
simple command header (for example, :RMODE SINGLE) the syntax is:
<function white space data c terminator
Compound Command Header. Compound command headers are a
combination of two or more program keywords. The first keyword selects
the subsystem, and the last keyword selects the function within that
Introduction to Programming an instrument HP 16518
1-4
Programming Reference