Siemens SIMATIC NET PROFIBUS manual Topologies with PROFIBUS-PA, Bus and Star Topology, Design

Topologies of SIMATIC NET PROFIBUS Networks

2.4Topologies with PROFIBUS-PA

Bus and Star Topology

With PROFIBUS-PA, the topology can be either a bus or star.

SpliTConnect System

The SpliTConnect tap (T tap) allows the structuring of a bus segment with DTE attachment points. The SpliTConnect tap can also be cascaded with the SpliTConnect coupler to form attachment distributors. Using the SpliTConnect terminator, the tap can be extended to become the segment terminator.

Star

Main cable

PROFIBUS-PA T tap

Tap line

DP/PA coupler (bus terminator integrated)

24 V DC PROFIBUS-DP

Figure 2-11 Bus and Star Topology

	Tap line
Distributor made		T tap with
up of T taps
		integrated
	Bus	bus terminator

Field devices attached via M12 connector

Field Device Power Supply via PROFIBUS-PA

When using the DP/PA bus coupler, the power for the field devices is supplied via the data line of PROFIBUS-PA.

Design

The total current of all field devices must not exceed the maximum output current of the DP/PA coupler. The maximum output current therefore limits the number of field devices that can be attached to PROFIBUS-PA.

PROFIBUS Networks SIMATIC NET	2-17
6GK1970-5CA20-0AA1 Release 2 05/2000