Section 4: Profibus Dp Description - Emerson Bettis XTE3000 Installation, Operation And Maintenance Manual

Installation, Operation and Maintenance Manual
MDE 256 Rev. 1

Section 4: PROFIBUS DP Description

PROFIBUS is a vendor-independent, open field bus standard used in a wide range of application
in process automation. Vendor independence and openness are ensured by the international
standards EN 50170 and EN 50254. The DP communication profile is designed for data exchange at
the field level. The central controllers (as PLC) communicate via serial connection with field devices
(as sensors and actuators). Data exchange is mainly cyclic. The central controller (called Master)
cyclically reads the input information from the field devices (called Slaves) and cyclically writes the
output information to the slaves. In addition, PROFIBUS DP provides communication services for
parameterization, alarm handling, and monitoring of intelligent field devices. The maximum number
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 maximum cable length is
1,200 m without repeaters.
Mono-master or multi-master system configuration can be provided. Bus access is controlled by token
passing procedure between masters and master-slave procedure (polling) between master and slaves.
Types of devices:
DP Master Class 1 (DPM 1):
DP Master Class 2 (DPM 2):
Slave:
Figure 2 shows a PROFIBUS DP configuration with two Master devices and different Slave devices.
Figure 2
PROFIBUS DP Description
Logical token ring between master devices
PLC
Drive
General
Slave devices
Section 4: PROFIBUS DP Description
This is the central controller that cyclically exchange information
with the field devices. Typical devices are PLC or PC
These devices are necessary for commissioning, maintenance
and diagnostics
Field device such transmitters, actuators, drives, etc.
PC
Transmitter
March 2022
Master
devices
XTE3000 Actuators
5