SRS Labs QMS 100 Series, Руководство пользователя

Страница: 129 / 280

Command Syntax 3-5
Technical Reference
Command Syntax
The RGA commands are ASCII character strings consisting of a two letter (case insensitive) command
name , a parameter , and a carriage return terminator .
Note: The carriage return character, decimal ASCII value=13, is represented throughout this manual
with the symbol <CR> . All command strings must be terminated with this character in order to be
acknowledged by the RGA.
Valid parameters are:
Numbers : Numbers are the most common type of parameter used to program the RGA. Number
parameters must be within a command-specific range and must not conflict with any pre-existing
parameter values of the ECU. Only Decimal format is accepted. The fractional parts are truncated to
four decimal places before being stored in memory. The '+' sign is optional for positive numbers. A zero
in front of the period is optional in fractional numbers with magnitude less than one.
Asterisk “
∗∗
” (default) : A single asterisk indicates that the default parameter value (stored in the RGA
ECU’s permanent memory) is to be used for command execution. The asterisk must be strictly
followed by a <CR>.
Question mark “?” ( Query ): Query commands are used to read error bytes, to measure total
pressure and to confirm internal parameter values. The question mark must be strictly followed by a
<CR> terminator. With a few exceptions, the data returned by most query commands is a string of
ASCII characters terminated by a linefeed (<LF>, decimal ASCII value=10) and a <CR> terminator:
string<LF><CR>.
No parameter : Some commands do not require a parameter.
The RGA assumes a potential command-string has been received over RS232 when a <CR>
character is detected in the serial interface. A c ommand handler immediately analyzes the string, and if
everything checks, the command is executed. However, if a problem is encountered a communication
error is reported and no command execution takes place.
The RGA has a 140 character input buffer and processes commands in the order received. If the buffer
fills up, the RGA will hold off handshaking on the RS232 interface using the CTS line. Similarly, the
RGA has a 32,000 character output buffer to store outputs until the host computer is ready to receive.
If either buffer overflows, the buffer is cleared and the error is reported. Linefeed characters (<LF>,
decimal ASCII value=10) and single carriage returns (<CR>, decimal ASCII value=13)) are ignored by
the serial interface.
Examples of command formats
The following list of commands activates the ionizer and triggers a single analog scan from 1 to 100 amu
at the default scan rate setting. Note that each one of the command character strings must be strictly
followed by a <CR> character in order to be detected by the RGA’s command handler.