Transmission Technique For Profibus-Pa - Siemens SIMATIC NET PROFIBUS Owner's Manual

1.2.7

Transmission 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:
S Simple cabling with twisted pair
S Remote power supply via the signal cores
S Intrinsically safe operation possible (for hazardous areas)
S Bus and tree topology
S Up to 32 nodes per cable segment
Restrictions:
S Transmission 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:
Medium:
Achievable segment lengths:
Transmission rate:
Number of nodes:
PROFIBUS Networks SIMATIC NET
6GK1970-5CA20-0AA1 Release 2 05/2000
Bus, star and tree topology
Shielded, twisted pair cable
1900 m
31.25 Kbps
Maximum 127 per network
PROFIBUS NETWORKS
1-15