User guide

56 MDX-ETHERNET User Guide
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Octet : A collection of 8 binary digits which form a byte.
Patch lead : A network cable where the terminal connections at one end of the cable
are connected straight through to the other end on a pin to pin basis. Normally used to
connect a network device to a network switch.
PC : Personal Computer.
PDU : Protocol Data Unit. This is the main Modbus message telegram, to which is
added the MBAP header to form the complete Modbus telegram.
PLC : Programming Logic Controller.
Polled data : See Cyclic data.
Router : A device that is used to connect different networks or subnets, in a similar way
to a firewall, however a router generally allows significantly less control of the data.
Shielding : A connection to provide additional immunity to noise used on a network
cable.
SMTP : Simple Mail Transfer Protocol. A protocol used for sending e-mail.
SNTP : Simple Network Time Protocol. A protocol used for synchronizing time over a
network.
Status word : A value that denotes the status of the drive. Each bit within the word will
have a specific meaning.
Subnet : A part of a network that has IP addresses in the same range. Devices on the
same subnet may communicate directly with other devices on the same subnet without
the use of a gateway.
Subnet mask : Defines which part of the IP address constitutes the subnet address and
which part constitutes the host device address.
Switch : A device that allows Ethernet devices to be interconnected.
TCP : Transmission Control Protocol, this protocol is responsible for ensuring that the
data on the network reaches it's destination.
URL : Uniform Resource Locator. A method used to give a web site a friendly name
such as www.leroy-somer.com as an alternative to an IP address.
VPN : Virtual Private Network. A method of using a non-secure or public network that
allows devices to be connected together as if they were a part of a private network.
Word : A collection of 16 binary digits.