Chapter 2
27
Overview of Remote Control
LAN remote control system
2.
O
ver
vie
w
o
f
Remote
Control
Control over telnet server
In a control system that operates over the telnet server, communications are performed
through connection between the sockets provided by the processes of the external
controller and the E4981A to establish a network path between them.
A socket is an endpoint for network connection; port 5024 and port 5025 are provided for
the sockets for the E4981A. Port 5024 is provided for conversational control using telnet
(user interface program for the TELNET protocol) and port 5025 for control from a
program.
Preparing the external controller
As in the case of the SICL-LAN server, you need to set the I/O interface of the external
controller in advance to establish communication to the E4981A using the TCP/IP
protocol. For the procedure, refer to
“Preparing the external controller” on page 24
“Control over SICL-LAN server”
section.
Conversational control using telnet (using port 5024)
You can use telnet to perform conversational control by sending SCPI commands to the
E4981A on a message-by-message basis. For telnet, the socket of port 5024 is used for
communications.
NOTE
For port 5024, service requests are asynchronous. Also, use
Ctrl+C
to clear the device.
In this example, to show you the control procedure using telnet, in a Windows environment
you control the E4981A from the external controller.
Step 1.
Open the MS-DOS command prompt screen.
Step 2.
At the MS-DOS prompt, type “telnet <IP Address>” and press Enter.
Step 3.
The telnet screen opens.
Step 4.
Type a command and press Enter; it is sent to the E4981A and executed. If you enter a
command that queries some data, the query response is displayed below the line in which
you entered the command.
shows the screen displaying the measured value with :FETC? after using the
:SOUR:FREQ command to set measurement frequency to 120Hz\1kHz, :CREJ? to check
the low C reject status. The setting check is made with the query after each setting.
Figure 2-4
Example of control using telnet
