The information that is exchanged between the controller (computer) and the device (PCR500M) is called a message.
The PCR-M uses the SCPI language for the messages.
There are two types of messages, commands that are sent from the computer to the PCR-M and responses that are sent from the PCR-M to the computer.
SCPI commands are ASCII-based commands designed for test and measurement devices. The command hierarchy is structured around the common root or node, which is the construction block of the SCPI sub system. A command consists of a program header, parameters, and punctuations.
The hierarchy is explained using the SOURce subsystem as an example.
Program header | Parameter | Hierarchy of node | |||
SOUR: | Roote node | ||||
FREQ | Second level | ||||
:LIM | Third level | ||||
:UPP | <numeric> | Fourth level | |||
:LOW | <bool> | Fourth level | |||
VOLT | Second level | ||||
:RANGE | Third level | ||||
:UPP | <numeric> | Fourth level | |||
:AUTO | <bool> | Fourth level |
A higher node is separated from a lower node using a colon (:).