Siemens SIMATIC NET PROFIBUS manual Monitoring FO Links, Mixed Structure

Topologies of SIMATIC NET PROFIBUS Networks

Monitoring FO Links

Using the echo function, the connected OLMs can monitor the fiber-optic sections. A break on a link is indicated by a display LED and by the signaling contact responding.

Even if only one transmission direction is lost, the segmentation triggered by the monitoring function leads to safe disconnection of the OLM from the star coupler. The remaining network can continue to work without problems.

Mixed Structure

The star coupler can be made up with combinations of OLM/P, OLM/G and OLM/G-1300 modules and at the RS-485 end with all types.

Redundant Optical Rings using OLMs

Redundant optical rings are a special form of bus topology. By closing the optical bus to form a ring, a high degree of operational reliability is achieved

S7-400

ET 200M À

À

4

S7-400

À

2

1

OP 25

À

4

À

1

Path 1

1

PG

À

3

À

1

Path 2

ÀTerminating resistor activated

1	FO cable	3	PROFIBUS 830-1T connecting cable
2	LAN cable for PROFIBUS	4	PROFIBUS 830-2 connecting cable

Figure 2-5 Network Structure in a Redundant, Optical, Two-Fiber Ring Topology

2-10	PROFIBUS Networks SIMATIC NET
	6GK1970-5CA20-0AA1 Release 2 05/2000