ProSoft Technology 5204-DFNT-PDPMV1 - Manual (Page 13)

PDPMV1 ♦ ProLinx Gateway Functional Overview
PROFIBUS DPV1 Master Protocol Manual
ProSoft Technology, Inc. Page 13 of 157
March 23, 2011
1.3.3 Token Passing
Token passing ring is the basis for communication between the more complex,
active stations. All stations have the same rights in that a token is passed from
station to station in a logical ring. The token is passed to each station with a
maximum, definable token cycle time. A station is given transmission rights for
the duration of time that it has the token.
1.3.4 Master/Slave Polling
Master/slave polling guarantees a cyclic, real-time based data exchange
between the station with transmission rights, the active station, and its
subordinates, the passive stations. In this case, the Master is able to pass data to
the slave and/or receive data. The services in layer 2 (field-bus data link in ISO-
OSI reference model) organize this communication.