BECKHOFF EtherCAT Technology Section I - Manual (Page 17)

ABBREVIATIONS
Slave Controller – Technology I-XVII
OPB On-Chip Peripheral Bus
Optional Service Optional services can be fulfilled by a PROFINET station in addition to the
mandatory services.
OSI Open System Interconnect
OUI Organizationally Unique Identifier –the first 3 Bytes of an Ethernet-Address that
will be assign to companies or organizations and can be used for protocol
identifiers as well (e.g. LLDP)
PDI Process Data Interface or Physical Device Interface: an interface that allows
access to ESC from the process side.
PDO Process Data Object
PDU Protocol Data Unit: Contains protocol information (Src Addr, Dest Addr,
Checksum and service parameter information) transferred from a protocol
instance of transparent data to a subordinate level (the lower level contains the
information being transferred).
PE Protection Earth
PHY Physical layer device that converts data from the Ethernet controller to electric
or optical signals.
Ping Frame that verifies whether the partner device is still available.
PLB Processor Local Bus
PLL Phase Locked Loop
PREOP Pre-Operational state of EtherCAT state machine
Priority Tagging Priority field inserted in an Ethernet frame.
Protocol Rules for sequences – here, also the sequences (defined in state machines)
and frame structures (described in encoding) of communication processes.
Provider Device that sends data to other consumers in the form of a broadcast message.
PTP Precision Time Protocol in accordance with IEEE 1588: Precise time
synchronization procedures.
PTP Master Indicates time in a segment.
PTP Slave Station synchronized by a PTP master.
Quad Cable Cable type in which the two cable pairs are twisted together. This strengthens
the electromagnetic resistance.
RAM Random Access Memory. ESC have User RAM and Process Data RAM.
Read Service enabling read access to an I/O device.
Real-Time Real-time capability of a system to perform a task within a specific time.
Request Call of a service in the sender/client.
Response Response to a service on the client side.