Siemens SIMATIC S5 Manual page 205

List of Abbreviations/Glossary
Setup time
Shortest station delay
SINEC L2
SINEC L2 local area
network
Slot time
SRD
Star coupler
Station
Station address
Status byte
Subminiature D connector
Subminiature D socket
T
Target rotation time
Terminating resistor
Terminator
Token
Token hold time
Token passing method
C-6
The time allowed to elapse between an event (e.g. receipt of a
character or expiry of an internal monitoring time) and the response
to that event ("dead time")
The shortest time elapsing between sending or receiving the last
bit of a frame and sending or receiving the first bit of the next
frame
SINEC L2 local area network
A bus-type LAN configuration consisting of one or more segments
coupled together by repeaters; used for networking PROFIBUS-
compatible PLCs and field devices at the cell and field levels
Wait-to-receive time (or wait-to-reply time); the length of time the
sender (initiator) of a frame must wait for the receiving station to
respond. It is immaterial whether this is a message or data frame or
a token frame.
Send and Request Data: Data transmission service provided by
layer 2 for acyclic send and request mode
active star coupler
Device/PLC capable of transmitting and receiving data via the LAN
bus
Each station has an address (assigned to it as a parameter) to
enable send and receive jobs to be uniquely assigned to it
Diagnostic byte for flagging the status of a job and any errors in
data transmission
9-pin plug or male connector to DIN 41652
9-pin socket or female connector to DIN 41652
The maximum permissible token rotation time
Resistance or resistance network used to match the line
impedance of LAN cables; terminating resistors are always required
at the end of the cable or segment
terminating resistors
A defined bit string ("assigned"/"unassigned") authorizing a station
to send data over the LAN
The difference between the target rotation time and the token
rotation time; the active station only has this time at its disposal for
sending data over the LAN
Bus access method when all stations are active;
the token (permission to send) is passed from one station to
another while all stations are logically interconnnected
S5-95U, SINEC L2
EWA 4NEB 812 6112-02