IEEE 1588
This standard defines a protocol enabling synchronisation of
clocks in distributed networked devices (e.g. connected via
Ethernet).
IP address
The IP address is the name of the unit in a network using the
Internet protocol. Refer to page 32.
Isochronous
Pertains to processes that require timing coordination to be
successful. Isochronous data transfer ensures that data flows
continuously and at a steady rate in close timing with the
ability of connected devices.
Isochronous Data
Data in a POWERLINK network which is to be transmitted
every cycle (or every nth cycle in case of multiplexed
isochronous data). Refer also to page 65.
Isochronous Period
The Isochronous Period of a POWERLINK cycle offers
deterministic operation, i.e. it is reserved for the exchange of
(continuous or multiplexed) isochronous data. Refer to page
65.
Legacy Ethernet
Ethernet as standardised in IEEE 802.3 (non-deterministic
operation in non-time-critical environments).
MAC address
The MAC address is an identifier unique worldwide consisting
of two parts: the first 3 bytes are the manufacturer ID and are
provided by IEE standard authority; the last three bytes
represent a consecutive number of the manufacturer. Refer to
page 32.
Managing Node (MN)
A node capable to manage the SCNM mechanism in a
POWERLINK network. Refer to page 63.
Media Access Control
(MAC)
One of the sub-layers of the Data Link Layer in the
POWERLINK reference model that controls who gets access to
the medium to send a message.
Multiplexed
Multiplexed is a POWERLINK communication class where
cyclic communication takes place in such a way that m nodes
are served in s cycles (the opposite to continuous).
Multiplexed CN
A node which is allowed to send isochronous data every n
th
cycle.
Multiplexed Timeslot
A slot destined to carry multiplexed isochronous data, i.e. the
timeslot is shared among multiple nodes.
NetTime
The MN’s clock time is distributed to all CNs within the SoC
frame.
Network Management
(NMT)
Network Management functions and services in the
POWERLINK model. It performs initialisation, configuration
and error handling in a POWERLINK network. Refer to page
70.
NMT State Machine
The state machine controlling the overall operating mode and
status of a POWERLINK node. Refer to page 70.
Object Directory
The repository of all data objects accessible over POWERLINK
communications.
