Connecting the field bus to the active field distributor AFS
Failure of field devices due to voltage dip
To prevent the failure of the field devices due to a voltage dip in the event of a fault, a
maximum voltage drop of 5 V between T1/T2 and Y must be assumed when using the AFS
without a downstream AFD.
The bus cables are guided into the enclosure by means of cable glands:
● The main line to the couplers using T1 and T2
● The spur cables to the line using Y (all Y terminal connections are equivalent)
Center feed: Loop-through of the line
If you loop-through the line on the AFS active field distributor using the cable gland Y, set the
bus termination switch to OFF on both FDC 157 couplers.
You connect the wires of the bus cable in the active field distributor on the terminal block
using screw-type terminals.
Active field distributors AFD4, AFD4 (FM), AFD8 and AFS
Product Information, 02/2015, A5E03775304-AC
2.5 Connecting the field bus to the active field distributor AFS
AFS terminal block
Installing and connecting