Technical data

Active components
4.5 Active components for the link from PROFIBUS DP to RS-232C
PROFIBUS Network Manual
98 System Manual, Edition 04/2009, C79000-G8976-C124-03
Area of application
● Active Field Distributor AFD
PA field devices, for example measuring instruments, sensors and actuators can be
connected to the active field distributor (AFD).
In conjunction with 2 DP/PA couplers (FDC 157-0), the active field distributor (AFD)
allows operation with ring redundancy. In this case, a maximum of 8 active field
distributors (AFD) connect 2 DP/PA couplers with the PA field devices. You can connect
up to 4 PA field devices to one active field distributor (AFD). The total number of PA field
devices on the PA line is 31 devices and this is limited by 1 A maximum current.
DP/PA coupler
AFD
AFDAFD
AFD
PROFIBUS-DP
PROFIBUS-PA
Figure 4-24 DP/PA coupler in redundant mode
● AFS (Active Field Splitter)
The active field splitter (AFS) connects 2 DP/PA couplers (FDC 157-0) with the field
devices of a PROFIBUS PA line. It therefore allows coupler redundancy on the PA line.
The total number of PA field devices on the PA line is 31 devices and this is limited by 1
A maximum current.
DP/PA coupler
AFS
PROFIBUS-DP
PROFIBUS-PA
Figure 4-25 Coupler redundancy with active field splitter (AFS)