Lake Shore Cryotronics Measure Ready M91 FastHall, Руководство пользователя

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www.lakeshore.com
Domain Name: A domain is a collection of network devices that are managed according
to some common characteristic of its members. Domains can contain subdomains,
which are subsets within the domain. The hierarchy can contain several dot-sepa-
rated levels which flow from right to left. For example, lakeshore.com contains the
top-level-domain “com” and the subdomain “lakeshore”. When using the Domain
Name System (DNS) to connect to a specific host device on a network, the device’s
hostname is tacked onto the left of the domain name. For example, the “www”” in
www.lakeshore.com refers to the Lake Shore web server, located within the internet
domain “lakeshore.com.”
4.4.2.4 TCP Socket Communication
A TCP socket connection interface is provided as the communication medium for the
network interface of the M91 FastHall™ measurement controller. A TCP socket con-
nection, or simply “socket connection”, is a common connection protocol used by
Ethernet devices. The Transmission Control Protocol (TCP) is commonly used for cre-
ating a communication channel between one program on one computer and one pro-
gram on another computer, for example a web browser on a PC and a web server on
the Internet.
In the case of the M91, the protocol is used to create a communication channel
between one program on one computer and the command line interface of the M91.
TCP uses error correction and collision avoidance schemes that make it a very reliable
form of network communication, but has drawbacks of having nondeterministic tim-
ing, and can encounter relatively large delays depending on network conditions.
These delays can be on the order of seconds. Sockets use port numbers to identify
sending and receiving endpoints on network devices. This allows for multiple sepa-
rate communication links to exist on each device.
The port number used for TCP socket connections on the M91 is 8888
.
4.4.3 SCPI over TCP There may be scenarios where the user desires to have the M91 connected to the
internet but does not want anyone to be able to connect to the M91 and start con-
trolling it. The SCPI over TCP setting allows for this. If the setting is disabled then net-
work connections are still allowed, allowing firmware or autodate time to still
function. For example, remote control of the M91 will not be allowed even if another
user knows the IP address and socket of the M91.
In order to issue SCPI commands over TCP and remotely control the instrument, this
setting needs to be enabled. This can be done by touching the switch, as shown below.
FIGURE 4-7
SCPI over TCP