
Installation, Operation and Maintenance Manual
VCIOM-17023-EN Rev. 7 February 2022
PROFIBUS DP Description 5
Section 5: PROFIBUS DP Description
Section 5: PROFIBUS DP Description
PROFIBUSisavendor-independent,openeldbusstandardusedinawiderangeofapplication
in process automation. Vendor independence and openness are ensured by the international 
standardsEN50170andEN50254.TheDPcommunicationproleisdesignedfordataexchangeat
theeldlevel.Thecentralcontrollers(asPLC)communicateviaserialconnectionwithelddevices
(as sensors and actuators). Data exchange is mainly cyclic. The central controller (called Master) 
cyclicallyreadstheinputinformationfromtheelddevices(calledSlaves)andcyclicallywritesthe
output information to the slaves. In addition, PROFIBUS DP provides communication services for 
parameterization,alarmhandlingandmonitoringofintelligentelddevices.Themaximumnumber
of Master and Slave devices in a bus segment is 32 without repeaters. With repeaters, the number can 
be extended to 126. The maximum cable length depends on the speed of transmission. Higher is the 
speed, shorter is the length. For instance, with baud rate 93.75 kb/s, the max cable length is 1,200 m 
without repeaters.
Mono-masterormulti-mastersystemcongurationcanbeprovided.Busaccessiscontrolledbytoken
passing procedure between masters and master-slave procedure (polling) between master and slaves.
Types of devices:
DP Master Class 1 (DPM 1): This is the central controller that cyclically exchange information 
withtheelddevices.TypicaldevicesarePLCorPC.
DP Master Class 2 (DPM 2): These devices are necessary for commissioning, maintenance 
and diagnostics.
Slave: Field device such transmitters, actuators, drives, etc.
Figure2belowshowsaPROFIBUSDPcongurationwithtwoMasterdevicesanddifferentSlavedevices.
Figure 2 
XTE3000 actuators
Logical token ring between master devices
Master 
devices
Slave devices
General Drive Transmitter
PLC PC