Active field distributor AFD4

Active field distributor AFD8

Active field distributor (AFD)

Active field distributors (AFD) can be operated in environments in accordance with Ex zone 2/22. They are offered in two versions 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 automatic 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 redundant 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 segment. 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 using plugs.

Active field distributor AFDiS

Active field distributor AFDiS

The active field distributor AFDiS (Active Field Distributor intrinsically Safe) can be operated in environments in accordance with Ex zone 1/21 and 2/22. It can integrate up to 6 intrinsically-safe PA or FF field devices into a fieldbus segment (line/ring) via its intrinsically-safe, short-circuit-proof spur line connections. Instead of the spur line, it is also possible to use a subsegment for 3 to 4 devices with a max. length of 500 m at connection S1 of the AFDiS. The spur lines with Ex [ia] type of protection as well as the subsegment can be routed into Zone 0/20.

Up to 5 field distributors AFDiS with a total of up to 31 field devices can be operated in a fieldbus segment. The limitation to 5 field distributors is also mandatory for mixed operation of AFD and AFDiS.

The number of field devices per segment additionally depends on the current consumption of the devices. A current of 1 A is available for all field devices of the segment.

With the integrated repeater function, the AFDiS has the following advantages compared to the AFD:

• Spur line lengths are independent of the total number of spur lines in the bus segment
• Spur line lengths need not be be taken into account when determining the total length of the bus segment

Under the following conditions, an AFDiS in a ring segment can be replaced during operation without failure of the segment: Installation in Zone 2/22 or in a non-hazardous area.

For compliance with IP66 protection, it is necessary to protect unused spur line connections using plugs.

Active field splitter AFS

The active field splitter (AFS) connects a PA or FF line segment with a redundant coupler pair of a PA or FF router. The AFS interconnects the line segment with the respective active coupler.

The PA or FF line segment can be connected to the AFS via one or two (center feed) equivalent Y-connectors out of a total of 4. For the center feed, the line segment is connected via the two Y-connectors (bus termination switch on both FDC 157 couplers set to "OFF").

For compliance with IP66 protection, it is necessary to protect unused connections using plugs.

AFS: Active field distributor for FOUNDATION Fieldbus H1