Endress+Hauser RID14, Руководство по эксплуатации

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RID14 Operating the field indicator
Hauser 23
available at: www.endress.com/download → Advanced → "Documentation code"
BA00034S.
6.3.1 System architecture
The following figure shows an example of a PROFIBUS® network with the associated
components.
0 - 10 bar
0 - 10 bar
PROFIBUS-DP
PROFIBUS-PA
IEC 61158-2
31.25 kbit/s
RID16 RID14
Visualization and monitoring
e. g. P View, FieldCare
and diagnostic software
Up to 32 devices per segment
PLC
segment
coupler
FISCO
segment
coupler
segment
coupler
A0021436-EN
 12 System integration with PROFIBUS® PA
PROFIBUS PA is always used in connection with a higher-level PROFIBUS DP control
system. Given that PROFIBUS DP and PROFIBUS PA have different transmission media and
baud rates, the PROFIBUS PA segment is integrated into the PROFIBUS DP system via a
segment coupler.
A segment coupler consists of a signal coupler and a bus power supply unit. One or more
transmission rates are supported on the PROFIBUS DP side, depending on the model. The
transmission rate for PROFIBUS PA is fixed at 31.25 kBit/s.
PROFIBUS PA has been specially designed to meet the needs of the process engineering
sector. Three features set it apart from a PROFIBUS DP system:
• PROFIBUS PA supports operation in hazardous areas without any special requirements.
• The devices are powered via the bus cable (two-wire devices)
• The data are transmitted via a physical layer according to IEC 61158-2 (MBP), allowing
users freedom in selecting the topology. With PROFIBUS PA, a tree structure, a line or a
combination of both can be selected for the topology. The fieldbus cable can be looped
through individual field devices but it is more advisable to connect the devices via a T-
junction with a short spur.
Field devices can be configured on the fly with PROFIBUS PA. The number of connected
fieldbus devices depends on different factors, such as use in a hazardous area, spur length,
cable types, current consumption of the field devices, etc.
The start and end of the bus segment must be terminated by a bus terminator.
No power should be supplied via the bus if configuring the PROFIBUS PA indicator
with the DTM via the CDI interface!
6.3.2 Bus access methods and data transmission
PROFIBUS PA uses the central master/slave principle as the bus access method. The PI
(process interface, e.g. PLC), a Class 1 master, is located on the PROFIBUS DP system. The