AT381x User's Guide
66
The terminator can be selected in the system configuration page, and the instrument defaults
is LF.
Note:
The AT381x allows the command sent by the host without the terminator, but it is
recommended to add the terminator at the end of the command. Otherwise, it will cause a
timeout wait after each command is received (the command timeout is 10ms~50ms
depending on the baud rate).
10.3
Terminator
Host can send a string of command to instrument, instrument terminator will begin parsing
after it captures end mark (LF, CR or LF+CR) or after input buffer overflows.
For example
：
Legal command string:
AAA:BBB CCC,DDD,EEE<LF>
AAA:BBB CCC,DDD,EEE<CR>
AAA:BBB CCC,DDD,EEE<LF+CR>
The AT381x terminator is responsible for parsing and performing all commands, before
programming, users must know about parsing rules.
10.3.1
Terminator Rules
1
．
Terminator only parses and responds ASCII code's data.
2
．
Command string must be ended with terminator, terminator will begin performing
command string only after it receives end mark or after
buffer overflows.
3
．
If command handshake is turned on, every time terminator receives one string, it will promptly
return this string to the host, only when host receives this returned string, can it continues
sending the next string.
4
．
After terminator parses error, it will promptly stop parsing, and the current command is
canceled.
5
．
When terminator parses the query command, it will terminate parsing this command string, the
latter command string will be ignored.
6
．
When parsing command string, terminator is case insensitive.
7
．
Terminator supports command abbreviated form, please refer to the latter chapter regarding
abbreviation norms.
10.3.2
Notation Conventions and Definitions
This chapter employs some marks, these marks are not a part of command tree; they are only
for better understanding of command string.
< >
the character in <> means this command's parameter
[ ]
the character in [] means optional command
{}
When there includes several parameter items in {}, means that users can only
choose one item from it.
( )
the abbreviated form of parameter is put in ()
Capital letter
Abbreviated form of command.
10.3.3
Command Structure
The SCPI commands are tree structured three levels deep. The highest level commands are called the subsystem