Siemens SIMATIC NET PROFIBUS manual Transmission Technique for PROFIBUS-PA, IEC 61158-2 Standard

PROFIBUS NETWORKS

1.2.7Transmission Technique for PROFIBUS-PA

IEC 61158-2 Standard

The transmission technique corresponds to the IEC 61158-2 standard (identical with EN 61158-2).

The transmission medium is a shielded, twisted pair cable. The signal is transmitted as a synchronous data stream Manchester-coded at 31.25 Kbps. In general, the data line is normally also used to supply power to the field devices.

Advantages:

SSimple cabling with twisted pair

SRemote power supply via the signal cores

SIntrinsically safe operation possible (for hazardous areas)

SBus and tree topology

SUp to 32 nodes per cable segment

Restrictions:

STransmission rate restricted to 31.25 Kbps

Characteristics of the IEC 61158-2 Transmission Technique

The main characteristics of the IEC 61158-2 transmission technique are as follows:

Network topology:	Bus, star and tree topology
Medium:	Shielded, twisted pair cable
Achievable segment lengths:	1900 m
Transmission rate:	31.25 Kbps
Number of nodes:	Maximum 127 per network

PROFIBUS Networks SIMATIC NET	1-15
6GK1970-5CA20-0AA1 Release 2 05/2000