Siemens SIMATIC NET PROFIBUS manual Cable Lengths for Plastic and PCF FO Paths, Fiber-optic cable

Configuring Networks

3.2.3Cable Lengths for Plastic and PCF FO Paths

The length of the transmission path on fiber-optic cables is not dependent on the transmission rate.

Each node on the optical PROFIBUS network has repeater functionality so that the following distance information relates to the distance between two adjacent, interconnected PROFIBUS nodes.

The maximum cable length between two PROFIBUS nodes depends on the type of fiber-optic cable used and the optical network components.

Table 3-7	Permitted Cable Lengths with Integrated Optical Interfaces or OBT
Fiber-optic cable		Maximum cable	For 1 Network (= 32
SIMATIC NET		lengths between two	nodes) (in m)
	PROFIBUS	nodes (in m)
Plastic fiber-optic,		50	1550
duplex cord
Plastic fiber-optic,		50	1550
standard cable
PCF fiber-optic,		300	9300
standard cable
Table 3-8	Permitted Cable Lengths in an OLM Network
Fiber-optic cable		Maximum cable	For 1 Network (= 32
SIMATIC NET		lengths between two	nodes) (in m)
	PROFIBUS	nodes (in m)
Plastic fiber-optic,		50	1550
duplex cord
Plastic fiber-optic,		80	2480
standard cable
PCF fiber-optic,		400	12400
standard cable

Note

SOptical buses can contain max. 32 integrated optical interfaces in series.

SSeveral buses of up to 32 integrated optical interfaces can only be linked via OBTs (optical repeaters).

SIn optical networks (bus, star, ring) containing only OLMs, the number of OLMs is limited to 122.

SThe number of all optical components (integrated interfaces, OBTs, OLMs) in the optical PROFIBUS network must be specified in the configuration tool as the “Number of OLM, OBT” parameter (see Section 3.3). This number must not exceed 122.

PROFIBUS Networks SIMATIC NET	3-17
6GK1970-5CA20-0AA1 Release 2 05/2000