5 Operation Promag 53 PROFIBUS-DP/-PA
70 Endress+Hauser
Confirming error messages
For the sake of plant and process safety, the measuring device can be configured in
such a way that fault messages (
) always have to be rectified and acknowledged
locally by pressing
.Only then do the error messages disappear from the display.
This option can be switched on or off by means of the “ACKNOWLEDGE FAULT MES-
SAGES” function (see the “Description of Device Functions” manual).
Note:
Notice messages (!) do not require acknowledgment. Note, however, that they remain
visible until the cause of the error has been rectified.
5.3 Communications: PROFIBUS-DP/-PA
5.3.1 PROFIBUS-DP/-PA technology
PROFIBUS (Process Field Bus) is a standardised bus system based on the European
standard EN 50170, Volume 2, which has been successfully used for many years in pro-
duction and process automation (chemical industry and process engineering).
The PROFIBUS is a multi-master bus system with high performance, which is particu-
larly suitable for medium to large plants.
PROFIBUS-DP
PROFIBUS-DP is a MASTER/SLAVE bus system. The master function is handled by an
automation control system (Class 1 master) or by one or more personal computers
(Class 2 master). Using cyclic data telegrams, the automation control system has full
access to all of the bus stations assigned to it. With a personal computer (Class 2 mas-
ter), you can, if needed, use acyclic data telegrams to exchange data with all of the con-
nected stations.
In accordance with the standard, up to 126 stations can be connected to a
PROFIBUS-DP network. The PROFIBUS-DP can operate at a transmission rate of 9.6
kBit/s...12 MBit/s and, at a transmission rate of 1.5 MBit/s, can support network expan-
sions of up to 2000 m with copper cables or 21,730 m using optical link modules.
PROFIBUS-PA
PROFIBUS-PA expands the PROFIBUS-DP by using an optimised transmission technol-
ogy for field devices while retaining the communications functions of the PROFIBUS-DP.
With the selected transmission technology, field devices can be connected via the
PROFIBUS-PA to automation control systems over great distances, even in hazardous
areas. PROFIBUS-PA is the communications compatible extension of PROFIBUS-DP.
PROFIBUS-PA = PROFIBUS-DP + optimised transmission technology for field devices
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