Emerson SI-PROFINET RT 0478-0125-02, User Manual

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SI-PROFINET RT User Guide
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Issue Number: 2
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IP subnet : A part of an IP network that consists of a range of addresses that may be
accessed by all devices on the same network directly.
ISO (International Standards Organization) : The International, voluntary standards
organization, closely aligned with the CCITT perhaps best noted for its OSI model and
OSI communications protocol. Membership includes other international organizations
issuing standards, with ANSI being the American representative.
Jitter : A tendency toward a lack of synchronization or other impairment caused by the
mechanical or electrical changes in communications equipment.
LAN (Local Area Network) : The data communications facilities used to provide
communications within a limited geographical area, normally up to 6 miles, using the
higher data rates normally from 1 Mbps to 1 Gbps. LANs may have bridges or gateways
to other networks but are usually confined to a building or cluster or buildings.
Latency : The waiting time, or delay between a device's request message and the
response message.
LED : Light Emitting Diode.
Long word : A 32-bit data word that may be signed or unsigned.
LSB : Least Significant Bit/Byte.
MAC address : This is a unique address that is assigned to SI-PROFINET RT at the
time of manufacture; no other device will have this address. The address is used to
make connections to the module before the IP address is assigned.
MSB : Most Significant Bit/Byte.
Network controller : The network device which controls the cyclic communication on a
network. ( See PLC ).
Network topology : The arrangement of devices and the links connecting the devices
on a network.
Node : A device on the network. This may be either a device such as a drive or part of
the network such as a repeater.
Non-crossover lead : See Patch lead.
Non-cyclic (explicit) data : Data that is requested or sent as required and not on a
regular basis. Sometimes referred to as "Explicit data".
Non-deterministic : A non-deterministic system is one where the output can not be
predicted with certainty. For communication systems, a non-deterministic system is one
where the messages can not be delivered at precise time intervals.
Octet : A collection of 8 binary digits which form a byte.