Technical data

60 Theoretical and general applications www.westermo.com
PROFIBUS DP
Represents basic, fast, cyclic and deterministic process data exchange between a bus
master and its assigned slaves. Communication between the master and slave is regu-
lated and controlled by the Master. A master is normally the central programmable
control system such as a PLC or industrial PC.
A slave is a field device (I/O terminal, drive equipment, HMI-station, valve, transmitter,
analysis instrument or similar) that reads information about the process and/or uses
output information to control the process. There are also units that only process input
or output information without effecting the process. From a communication stand-
point slaves are passive participants that only respond to a direct enquiry.
Data communication between DPM1 (DP Master class 1) and its assigned slaves is
taken care of automatically, according to a defined repeated sequence. The user per-
forms slave assignment when configuring the bus system at the same time as determin-
ing which slaves are to be included /excluded in the cyclic communication.
Master and slave
Cyclic data
communication
between DPM1
and the slaves
DP Master
Class 1
DP slaves
Head
Telegram call
Telegram answer
DP Master
DP Slave
EndExits
Head EndEntrance
B A C K