TDK-Lambda HFE1600 SERIES, Руководство пользователя

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7. PROGRAMMING USING SOCKETS
7.1 Socket Description
The VISA drivers for the HFE LAN module with LAN are popular in the Test and Measurement
world. However, some customers cannot use VISA because of installation or licensing
issues or because the controller (i.e.: industrial PLC) does not have support for VISA.
If you cannot use VISA drivers, then the HFE LAN offers socket connections. This is low-
level LAN protocol that is universally available in all operating systems and programming
environments.
7.2 Communicating Using Sockets
Communicating through sockets involves opening a socket connection, sending text
commands and reading the responses. The functions a programming language use to
manage the socket is called the TCP or UDP stack.
There are two types of socket protocols which may be used, TCP and UDP. Each has its
own port number.
7.3 Controller Access: Single and Multiple Clients
The web page has a security setting to limit or enable the types of connections and
numbers of control computers (called “clients”) that may be connected in parallel.
The rules for the One Client/Multiple Clients are:
One Client Only Multiple Clients
Web Page
Not logged-in Max 2 copies of web pages may be open at any time.
You may view but cannot change the module operation.
Web Page
Logged-in as “admin”
You cannot log in if a VISA or socket port is already open.
If you are logged in, any other connections are blocked.
Only one additional copy of web page may be opened.
VISA Connection Only one VISA port may be open at one time.
Only one copy of web page may be opened.
TCP Socket
UDP Socket
TCP socket may be opened.
UDP sockets are blocked.
Only one copy of web
page may be opened.
Single connection of UDP or
maximum 2 connections of
TCP are allowed at the same
time.
Table 8: One client/Multiple clients rules.
Note - It is prohibited to run combinations other than that specified.
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