Ceyear 4051 Series, User Manual

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6 Remote control
6.1 Basis of Remote Control
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Library applied in UNIX and Winsock Library applied in Windows constitute the two common socket
libraries.
The socket of the signal/spectrum analyzer is compatible with the Berkeley socket and Winsock through the
application program interface (API). Besides, it is also compatible with other standard socket API. The
command will be sent by the socket program to control the signal/spectrum analyzer through SCPI commands.
The signal/spectrum analyzer has a fixed socket port number of 5000.
6.1.1.2 GPIB Interface
As the only bus dedicated to instrument control, GPIB is still widely applied in automatic test systems. The
4051 signal/spectrum analyzer integrated GPIB interface on the rear panel. In order to realize remote control,
the master control computer should be configured with the GPIB bus card, drive program and VISA library in
advance. During communication, the controlled instrument is addressed by the master control computer
according to the GPIB bus address and users may change such GPIB address to prevent communication
failure caused by address conflict in the entire system.
Refer to ANSI/IEEE 488.1-1987 and ANSI/IEEE 488.2-1992 for details of descriptions of GPIB and relevant
interfaces. For details, visit the IEEE website http://www.ieee.org.
Pay attention to the following when connecting the GPIB interface:
 Only 15 pieces of equipment are allowed at most in the test system connected with GPIB bus;
 The total length of the transmission cable must not exceed 20m or twice of the number of instruments in
the system.
 Generally, the maximum length of the transmission cable between devices must not exceed 2m.
 For parallel connection of instruments, use ―or‖ connecting lines.
 Connect the terminal of the IEC bus cable to the instrument or controlling computer.
6.1.2 Message
Messages transmitted through the data lines are divided into the following two types.
1) Interface message
Interface messages are unI/Que to GPIB bus and only instruments with GPIB bus function are able to respond
to such messages. When the master control computer sends interface messages to the instrument, the attention
line should be lowered at first before interface messages can be transmitted to the instrument via the data line.
2) Instrument message
For the structure and grammar of instrument messages, refer to ―5.1.4 SCPI Commands‖. According to the
transmission direction, instrument messages can be divided into the command and instrument response.
Unless otherwise specified, the same method should be applied for use of instrument messages with the
remote control interface.
a) Commands
The command (programming message) is a kind of message transmitted by the master control computer to the
instrument, used for remote control of the instrument function and query of the status information. Commands
are divided into the following two types:
 According to the influence on the instrument:
—
Setting command: change the instrument setting status, such as resetting, frequency setting, etc.
—
Query command: inquire and return data, such as instrument identification or parameter query. The query
command ends with a suffix question mark.
 According to the definition in the standard: