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Appendix B Command Syntax and Style
Command Types, Format, and Elements
Operating and Programming Guide B-3
Command Types, Format, and Elements
Command Types
There are two types of GPS Receiver programming commands: IEEE
488.2 Common Commands and Standard Commands for
Programmable Instruments (SCPI). The IEEE 488.2 Common
Commands control and manage communications between the
Receiver and the controller, terminal, or personal computer. The SCPI
commands control instrument functions. The format of each type of
command is described in the following paragraphs.
Command Formats
Common Command Format
The IEEE 488.2 Standard defines the Common commands as
commands that perform functions like reset, self-test, status byte
query, and identification. Common commands always begin with the
asterisk (*) character, and may include parameters. The command
keyword is separated from the first parameter by a space character.
Some examples of Common commands are as follows:
*IDN? *ESE 32
SCPI Command and Query Format
SCPI commands perform functions like instrument setup. A subsystem
command has a hierarchical structure that usually consists of a top
level (or root) keyword, one or more lower-level keywords, and
parameters. The following example shows a command and its
associated query:
:GPS:POSition:SURVey:STATe ONCE
:GPS:POSition:SURVey:STATe?
GPS is a root-level keyword with POSition the second-level keyword,
SURVey the third-level keyword, and STATe the fourth-level. ONCE is
the command parameter.