Profibus Communications; Profibus Dp Transmission Technology; Acronyms And Abbreviations; Profibus Interface - ABB Navigator 540 Instruction Manual

4 PROFIBUS communications

This section contains information specific to the
®
PROFIBUS -enabled Navigator AWT540 with RS485 physical
layer.
It must be read in conjunction with the associated Operating
instructions:
— Sodium: OI/ASO550-EN
— Dissolved oxygen: OI/ADS550-EN
— Hydrazine: OI/AHM550-EN
Refer the associated data sheets for details of specific order
codes:
— Sodium: DS/ASO550-EN
— Dissolved oxygen: DS/ADS550-EN
— Hydrazine: DS/AHM550-EN

4.1 PROFIBUS DP transmission technology

The most common transfer method of PROFIBUS-DP is RS485
– a proven technology. A twisted, shielded, 2-wire copper
cable is used as the transfer medium.
The bus structure enables addition and removal of stations or
step-by-step commissioning of the system without affecting
other stations. Later expansion has no influence on stations
already in operation.
Transmission speeds from 9.6 kbps up to 12 Mbps are
supported. One uniform transmission speed is selected for all
devices on the bus when the system is commissioned.

4.2 Acronyms and abbreviations

Input Data passed into a Master device
(for example, from a Slave device)
I&M PROFIBUS identification
and maintenance function
MS1 Class 1 Master-Slave acyclic transaction
Output Data passed out of a Master device
(for example, to a Slave device)
PCS/DCS Process control system /
distributed control system
PI/PNO PROFIBUS International / PROFIBUS User
Organization (www.profibus.com)
TB PROFIBUS-PA transducer block
TOT Totalizer function block
Table 4.1: Acronyms and abbreviations
8 COM/AWT540/PB–EN Rev. C | Navigator 540 | Transmitter

4.3 PROFIBUS interface

Physical layer RS485
Supported baud rates 9.6 kbps to 12 Mbps
Supported DP Protocol DPV0, DPV1
services
Concurrent MS2 3
connections
Device stub length 250 mm (9.8 in.)
Application profile PA version 3.01
Master components GSD, DTM, EDD
available
Table 4.2: PROFIBUS interface

4.4 Installation

4.4.1 Installation overview

All devices are connected in a bus structure ('line') as shown in
Fig 4.1. Up to 32 stations (master or slaves) can be linked to
create one 'segment', although it is recommended not to install
more than 16 devices on a single segment.
Each end of a segment must be terminated by an active bus
terminating resistor. Both bus terminators must always be
powered to ensure fault-free operation, therefore it is strongly
recommended that they are connected to a back-up power
supply. The use of bus amplifiers (repeaters) and segment
couplers can be used to extend the network.
Engineer
Operational
level
Master
Control
level
Slave
level
DP / PA link
Fig. 4.1: Typical PROFIBUS network
Operate
PROFIBUS-DP
Navigator AWT540
transmitter
PROFIBUS-P