Stanford Research Systems DS335, Руководство пользователя

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3-2 Programming Commands
DS335 Synthesized Function Generator
There is no need to wait between commands. The DS335 has a 256
character input buffer and processes commands in the order received. If the
buffer fills up the DS335 will hold off handshaking on the GPIB and attempt
to hold off handshaking on RS232. If the buffer overflows the buffer will be
cleared and an error reported. Similarly, the DS335 has a 256 character
output buffer to store output until the host computer is ready to receive it. If
the output buffer fills up it is cleared and an error reported. The GPIB output
buffer may be cleared by using the Device Clear universal command.
The present value of a particular parameter may be determined by querying
the DS335 for its value. A query is formed by appending a question mark "?"
to the command mnemonic and omitting the desired parameter from the
command. If multiple queries are sent on one command line (separated by
semicolons, of course) the answers will be returned in a single response line
with the individual responses separated by semicolons. The default
response terminator that the DS335 sends with any answer to a query is
carriage return-linefeed <cr><lf> on RS232, and linefeed plus EOI on GPIB.
All commands return integer results except as noted in individual command
descriptions.
Examples of Command Formats
FREQ, 1000.0 <lf> Sets the frequency to 1000 Hz.
FREQ? <lf> Queries the frequency.
*IDN? <lf> Queries the device identification (query, no
parameters).
*TRG <lf> Triggers a sweep (no parameters).
FUNC 1 ;FUNC? <lf> Sets function to square wave(1) then queries the
function.
Programming Errors The DS335 reports two types of errors that may occur during command
execution: command errors and execution errors. Command errors are
errors in the command syntax. For example, unrecognized commands,
illegal queries, lack of terminators, and non-numeric arguments are examples
of command errors. Execution errors are errors that occur during the
execution of syntactically correct commands. For example, out of range
parameters and commands that are illegal for a particular mode of operation
are classified as execution errors.
No Command Bit The NO COMMAND bit is a bit in the serial poll register that indicates that
there are no commands waiting to be executed in the input queue. This bit is
reset when a complete command is received in the input queue and is set
when all of the commands in the queue have been executed. This bit is
useful in determining when all of the commands sent to the DS335 have
been executed. This is convenient because some commands, such as
setting the function or sweep, take a long time to execute and there is no
other way of determining when they are done. The NO COMMAND bit may
be read while commands are being executed by doing a GPIB serial poll.
There is no way to read this bit over RS232. Note that using the *STB?
query to read this bit will always return the value 0 because it will always
return an answer while a command is executing- the *STB? command itself!
DETAILED COMMAND LIST The four letter mnemonic in each command sequence specifies the
command. The rest of the sequence consists of parameters. Multiple