D-8
Series 90™-30 PLC LONWORKS® Bus Interface Module User's Manual
–
June 1997
GFK-1322A
D
Server
EXAMPLE: File server, print
server, mail server.
A network node that provides specific services to other network
nodes (clients). (See also Client.)
Service Request Transfer Protocol
(SRTP)
A proprietary protocol that encodes Series 90 “Service Requests”, the
native language of the Series 90 PLC CPUs, to provide general
purpose communications with a Series 90 PLC. SRTP is presently
available over 802.3/Ethernet networks. SRTP is also used by
Logicmaster 90 to communicate over an Ethernet network.
Signal Quality Error (SQE)
An indication from the MAU (transceiver) to the Ethernet Interface
to indicate any of three conditions: 1) improper signals received
from the medium, 2) collision detected, or 3) SQE message test.
Slot Time ( in a CSMA/CD
network)
Minimum bitrate-dependent unit of time which, in case of collision,
is used to determine the delay after which network nodes may
attempt to retransmit. [Slot time for all IEEE 802.3 10 Mbps
implementations is 51.2
µ
sec (512 bit times)].
Soft Switches
Basic system information set up by the Logicmaster 90 Configurator
and transferred to the LAN Interface upon powerup or restart.
Station
A computer, PLC, or other device that connects to one or more
networks. (See also Node.)
Station Address
Each node on an Ethernet network must have a unique MAC address
which is different from all other nodes on the network. This is a 12-
hexadecimal digit MAC address. (See also MAC Address.)
Station Manager
A part of the basic Ethernet Interface communications software that
executes as a background activity on the Ethernet Interface. The
Station Manager provides interactive supervisory access to the
Ethernet Interface. The Station Manager may be accessed locally via
the serial port, or remotely over the LAN.
Tally
Counters kept by the LAN Interface to indicate load and performance
information.
Topology
The pattern formed by the physical medium interconnecting the
nodes of a network.
Transceiver
See Medium Attachment Unit (MAU).
Transceiver Cable
See Attachment Unit Interface (AUI).
Transmission Path Delay
The time required for a bit to travel between the two most distant
network nodes in a bus network.
Transmission Control Protocol
(TCP)
The Internet standard connection-oriented transport level protocol.
See also Internet Protocol (IP).
Universal Address Administration
See Global Address Administration.
Word
A measurement of memory length, usually 4, 8, 16, or 32 bits long.
In the Series 90 PLC, a word is always 16 bits.
Summary of Contents for 90-30 PLC
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