SIEMENS
3/80
Siemens IK PI · 2015
PROFIBUS
Electrical networks (PROFIBUS PA)
Active field distributors
3
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Overview
Active field distributor (AFD)
Active field distributor AFD4
Active field distributor AFD8
Active field distributors (AFD) can be operated in environments
in accordance with Ex zone 2/22. They are offered in two ver-
sions which differ as follows:
•
AFD4 with 4 spur line connections for 1 field device each
•
AFD8 with 8 spur line connections for 1 field device each
An AFD4 can therefore connect up to 4 field devices, and an
AFD8 can connect up to 8 field devices, via short-circuit proof
spur line connections to a fieldbus segment (line/ring) with auto-
matic bus termination. This applies to both PA (PROFIBUS PA)
as well as FF (FOUNDATION Fieldbus H1) field devices.
The fieldbus segment can be connected to a single or redun-
dant PROFIBUS DP via a PA or FF router and can thus be
seamlessly integrated into the SIMATIC PCS 7 process control
system.
Up to 8 active field distributors AFD4/AFD8 with a total of up to
31 connected field devices can be operated per fieldbus seg-
ment. The number of field devices is also limited by the current
consumption of the field devices. A maximum of 60 mA per spur
line and a maximum of 1 A per segment is available for the field
devices.
An AFD in a ring segment can be replaced during operation
without failure of the segment.
For compliance with IP66 protection, it is necessary to protect
unused spur line connections by plugs.
© Siemens AG 2014