List of Abbreviations/Glossary S5-95U, SINEC L2
C-6
EWA 4NEB 812 6112-02
Setup time 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")
Shortest station delay 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 SINEC L2 local area network
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
Slot time 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.
SRD Send and Request Data: Data transmission service provided by
layer 2 for acyclic send and request mode
Star coupler active star coupler
Station Device/PLC capable of transmitting and receiving data via the LAN
bus
Station address Each station has an address (assigned to it as a parameter) to
enable send and receive jobs to be uniquely assigned to it
Status byte Diagnostic byte for flagging the status of a job and any errors in
data transmission
Subminiature D connector 9-pin plug or male connector to DIN 41652
Subminiature D socket 9-pin socket or female connector to DIN 41652
T
Target rotation time The maximum permissible token rotation time
Terminating resistor 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
Terminator terminating resistors
Token A defined bit string ("assigned"/"unassigned") authorizing a station
to send data over the LAN
Token hold time 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
Token passing method 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
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