Siemens SIMATIC NET PROFIBUS manual Rules

Topologies of SIMATIC NET PROFIBUS Networks

Rules

The following rules must be taken into account when extending PROFIBUS-PA:

SThere can be a maximum of 31 PA field devices in a PROFIBUS-PA system

SOnly one device supplying power (=DP/PA coupler) can be connected in a physical PROFIBUS-PA segment.

SA maximum of 31 PA field devices can be attached to a DP/PA link. The maximum number of attachable PA field devices per physical PROFIBUS-PA segment or per DP/PA coupler is limited by the maximum output current of the DP/PA coupler and the I/O data to be transferred.

PROFIBUS Networks SIMATIC NET	2-27
6GK1970-5CA20-0AA1 Release 2 05/2000