Siemens SIMATIC S5 Manual page 203

List of Abbreviations/Glossary
Field device
Field level
FMA services
FO transmission
technology
G
GAP
I
Implicit communications
Indication
L
LAN access method
Layer 2
Layer 2 services
Local station
Longest station delay time
M
Master-slave method
Multicasting
O
C-4
A device, such as a sensor or actuator, permitting the exchange of
information between the control system and the process
A hierarchical level in an integrated automation system; the
interchange of information between the control system and the
process is implemented by means of field devices, sensors and
actuators
Debugging and diagnostic services for monitoring the network and
the local stations; implement network management functions to the
PROFIBUS standard
Configuration of the SINEC L2 LAN using optical fiber conductors
or waveguides (necessary in noisy environments)
Address area of the active station extending from its own address
to that of the next active station
Data communications over the LAN take place automatically and
are not initiated by the user program
Indication of an event
Controls access to the transmission medium by the stations to
guarantee the functional interchange of data
master-slave method
token passing method
Layer 2 of the ISO (International Organization for Standardization)
7-layer reference model for communications; in PROFIBUS terms,
layer 2 is referred to as the Fieldbus Data Link (FDL)
Communications mechanisms provided to the user by the layer 2
firmware of the communications processor
Initiator of a communications link, either as a sending or requesting
station
The longest time elapsing between sending or receiving the last bit
of a frame and the sending or receiving of the first bit of the next
frame
LAN access method when there is only one station active and all
other stations are passive; only the active station automatically has
the right to send, while all passive stations can send data to an
active station only when requested to do so by that station
Transmitting from an active station to a group of active and passive
stations
S5-95U, SINEC L2
EWA 4NEB 812 6112-02