Ceyear 3943B, Руководство по эксплуатации

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6 Remote control
6.1 Remote control principals
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1) Interface message
During communication between the instrument and the host computer, the ―attention‖ cable shall be
pulled down first before the interface messages can be transmitted to the instrument via the data cable.
Only the instruments with GPIB bus function can send interface messages.
2) Instrument message
For the structure and syntax of instrument messages, refer to Section "5.1.4 SCPI Commands".
Depending on the transmission direction, instrument messages can be divided into commands and
instrument responses. Unless otherwise stated, all remote control interfaces apply instrument message
in the same way.
a) Commands:
Commands (programming messages) are messages sent by the host computer to the instrument for
remote control of instrument functions and query of status information. Commands are divided into the
following two categories:

Based on the impact on the instrument:
-- setting commands: change the set state of the instrument, such as reset or setting frequency.
-- query commands: query and return data, for example: identify the instrument or query the parameter
value. Query commands end with the suffix question mark.

Based on the definition in the standard:
- Generic commands: function and syntax defined by IEEE 488.2, applicable to all types of instruments
(if implemented)
The purpose is for management of standard status register, reset and self-detection, etc.
-- instrument control commands: instrument characteristic commands, used to realize instrument
functions, such as setting frequency.
The syntax also follows the SCPI specification.
b)
Instrument responses:
Instrument responses (response message and service request) are the query result information sent by
the instrument to the computer. Such information includes measurement results, instrument status, etc.
6.1.3 SCPI commands
6.1.3.1 Introduction to the SCPI command
SCPI (Standard Commands for Programmable Instruments) is a command set built on the standard
IEEE488.2 and suitable for all instruments. The main purpose is to make the same function have the
same program command to achieve the universality of program control commands.
The SCPI command consists of a command header and one or more parameters, which are separated
by a space, and the command header contains one or more key fields. The command is directly suffixed
with a question mark as the query command. Commands are divided into common commands and
instrument commands that have different syntactic structures. The SCPI command has the following
characteristics:
1) The remote control commands are oriented towards the test function and do not describe the
instrument operation.
2) The remote control commands reduce the repetition of the process of implementing similar test
functions and ensure the compatibility of programming.
3) The remote control messages are defined in layers that are hardware independent of the
communication physical layer.
4) The remote control commands are independent of the programming method and language, and the
SCPI test program is easily portable.
5) The remote control commands are scalable and can adapt to different scale of measurement