ELPRO 215U-2, Руководство пользователя

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59
User Manual MN032EN
Effective October 2017
215U-2 802.11
wireless I/O and gateway
EATON
www.eaton.com
Term Definition
RSSI Received signal strength indicator (RSSI) is a measurement of the power present in a received radio signal. In an IEEE 802.11 system,
RSSI is the relative received signal strength in a wireless environment, in arbitrary units. RSSI is an indication of the power level being
received by the antenna. Therefore, the higher the RSSI number (or less negative in some devices), the stronger the signal.
Transmit Power The power at which the wireless devices transmits, usually expressed in mW or dBm.
MAC Address
Media Access Control (MAC) address is a unique code assigned to most forms of networking hardware. The address is permanently
assigned to the hardware, so limiting a wireless network’s access to hardware (such as wireless cards) is a security feature employed
by closed wireless networks. But an experienced hacker armed with the proper tools can still figure out an authorized MAC address,
masquerade as a legitimate address, and access a closed network.
Every wireless 802.11 device has its own specific MAC address hard-coded into it. This unique identifier can be used to provide
security for wireless networks. When a network uses a MAC table, only the 802.11 radios that have had their MAC addresses added to
that network’s MAC table will be able to get onto the network.
Modbus Modbus is a serial communications protocol for use with its programmable logic controllers (PLCs).
PLC A programmable logic controller (PLC) is a digital computer used for automation of electromechanical processes, such as control of
machinery on factory assembly lines, amusement rides, or light fixtures.
Proxy Server Used in larger companies and organizations to improve network operations and security, a proxy server is able to prevent direct
communication between two or more networks. The proxy server forwards allowable data requests to remote servers and/or responds
to data requests directly from stored remote server data.
RJ-45 Standard connectors used in Ethernet networks. RJ-45 connectors are similar to standard RJ-11 telephone connectors, but RJ-45
connectors can have up to eight wires, whereas telephone connectors have four.
RTU
A remote terminal unit (RTU) is a microprocessor-controlled electronic device that interfaces objects in the physical world to a
distributed control system or SCADA system by transmitting telemetry data to a master system, and by using messages from the
master supervisory system to control connected objects.
SCADA SCADA (supervisory control and data acquisition) is a type of industrial control system (ICS). Industrial control systems are computer
controlled systems that monitor and control industrial processes that exist in the physical world. SCADA systems historically
distinguish themselves from other ICS systems by being large scale processes that can include multiple sites, and large distances.
Server A computer that provides its resources to other computers and devices on a network. These include print servers, Internet servers and
data servers. A server can also be combined with a hub or router.
SMA SMA (SubMiniature version A) connectors are semi-precision coaxial RF connectors for coaxial cable with a screw type coupling
mechanism. The connector has a 50 Ω impedance. It is designed for use from DC to 18 GHz.
Sub Network or Subnet Found in larger networks, these smaller networks are used to simplify addressing between numerous computers. Subnets connect
together through a router.
Switch
A type of hub that efficiently controls the way multiple devices use the same network so that each can operate at optimal performance.
A switch acts as a networks traffic cop: rather than transmitting all the packets it receives to all ports as a hub does, a switch
transmits packets to only the receiving port.
TCP Transmission Control Protocol (TCP) isprotocol used along with the Internet Protocol (IP) to send data in the form of individual units
(called packets) between computers over the Internet. While IP takes care of handling the actual delivery of the data, TCP takes care
of keeping track of the packets that a message is divided into for efficient routing through the Internet. For example, when a Web
page is downloaded from a Web server, the TCP program layer in that server divides the file into packets, numbers the packets, and
then forwards them individually to the IP program layer. Although each packet has the same destination IP address, it may get routed
differently through the network. At the other end, TCP reassembles the individual packets and waits until they have all arrived to
forward them as single message.
TCP/IP The underlying technology behind the Internet and communications between computers in a network. The first part, TCP, is the
transport part, which matches the size of the messages on either end and guarantees that the correct message has been received.
The IP part is the user’s computer address on a network. Every computer in a TCP/IP network has its own IP address that is either
dynamically assigned at startup or permanently assigned. All TCP/IP messages contain the address of the destination network as well
as the address of the destination station. This enables TCP/IP messages to be transmitted to multiple networks (subnets) within an
organization or worldwide.
TTL Transistor–transistor logic (TTL) is a class of digital circuits built from bipolar junction transistors and resistors. It is called TTL logic
because both the logic gating function (AND) and the amplifying function are performed by transistors.
WAN Wide area network (WAN) is a communication system of connecting PCs and other computing devices across a large local, regional,
national or international geographic area. Also used to distinguish between phone-based data networks and Wi-Fi. Phone networks are
considered WANs and Wi-Fi networks are considered Wireless Local Area Networks (WLANs).
Wi-Fi Wireless Fidelity. An interoperability certification for wireless local area network (LAN) products based on the Institute of Electrical
and Electronics Engineers (IEEE) 802.11 standard.