Description
The PROFIBUS OLMs are designed for use in optical PROFIBUS field bus networks. They enable the conversion of electrical PROFIBUS interfaces (RS485) into optical PROFIBUS interfaces and vice versa.

When commissioning the PROFIBUS OLMs check the DIP switches and set them according to the network topology you have.

You can achieve the topologies below with the PROFIBUS OLMs:

• Line topology
• Star topology
• Redundant optical ring

Combinations of these basic types are also possible.

Line topology
The figure below shows the setup of a line topology.

Fig. 01

Star topology
The figure below shows the setup of a star topology.

Fig. 02

Redundant optical ring
The figure below shows the setup of a redundant optical ring.

Fig. 03

Line with fiber optic cable segment monitoring and segmenting
The OLMs can be operated in "Line with fiber optic cable segment monitoring and segmenting" mode or "Line without fiber optic cable segment monitoring".
Use the "Line with fiber optic cable segment monitoring and segmenting" mode if a defective fiber optic cable segment is to be disconnected from the rest of the network. If a module fails or if a fiber optic cable breaks or faults are detected on the optical transmission path, the fiber optic cable segment between the two OLMs is interrupted (segmented). The PROFIBUS network splits into two subnetworks. Each one remains fully functional. The fault is signaled by the channel LEDs switching to red and activation of the alarm contacts of the two OLMs connected to the defective fiber optic cable segment. The segmentation is cleared automatically as soon as both modules recognize the segmented field bus subnetwork as undisrupted through independently sent test messages.

Setting of the DIP switches for line topology
The table below shows the settings of the DIP switches on the PROFIBUS OLM V4.0 / V3 for setup of a line topology with and without fiber optic cable segment monitoring. In this example no OLMs of the previous generation SINEC L2FO OLM / P3, -P4, -S3, -S4, S3-1300 and S4-1300 are used in the line topology.
 

DIP switch	Meaning	Line without fiber optic cable segment monitoring	Line with fiber optic cable segment monitoring
S0	Operating mode of the electrical channel CH1 Setting 0 = electrical channel with segment monitoring Setting 1 = electrical channel without segment monitoring	0	0
S1	Operating mode of the optical channel CH2	1	0
S2	Operating mode of the optical channel CH2	0	0
S3	Operating mode of the optical channel CH3	1	0
S4	Operating mode of the optical channel CH3	0	0
S5	Transmission power of CH2 with OLM / P11, OLM / P12 and OLM / P22 Setting 1 = default Setting 0 = reduction if when using plastic fiber optic cable on CH2 an overload occurs or if the fiber optic cable length is less than 30m	0	0
S6	Transmission power of CH3 with OLM / P11, OLM / P12 and OLM / P22 Setting 1 = default Setting 0 = reduction if when using plastic fiber optic cable on CH3 an overload occurs or if the fiber optic cable length is less than 30m	0	0
S7	Switch on or off function compatibility with devices of the previous generation SINEC L2FO OLM / P3, -P4, -S3, -S4, S3-1300 and S4-1300.	0	0
S8	Operating mode of the electrical channel CH0 with OLM / P22 and OLM / G22 Setting 0 = electrical channel with segment monitoring Setting 1 = electrical channel without segment monitoring	0	0

Setting of the DIP switches for star topology
The table below shows the settings of the DIP switches on the PROFIBUS OLM V4.0 / V3 for setup of a star topology with and without fiber optic cable segment monitoring. In this example no OLMs of the previous generation SINEC L2FO OLM / P3, -P4, -S3, -S4, S3-1300 and S4-1300 are used in the star topology.
 

DIP switch	Meaning	Star without fiber optic cable segment monitoring	Star with fiber optic cable segment monitoring
S0	Operating mode of the electrical channel CH1 Setting 0 = electrical channel with segment monitoring Setting 1 = electrical channel without segment monitoring Note For all OLMs that are connected to the electrical star segment CH1 / CH0 must be switched to "Monitor off" mode (S0/S8=1). This switches off the segmenting function of the RS485 channel for these OLMs in order to achieve higher availability of the electrical star.	1	1
S1	Operating mode of the optical channel CH2	1	0
S2	Operating mode of the optical channel CH2	0	0
S3	Operating mode of the optical channel CH3	1	0
S4	Operating mode of the optical channel CH3	0	0
S5	Transmission power of CH2 Setting 1 = default Setting 0 = reduction if when using plastic fiber optic cable on CH2 an overload occurs or if the fiber optic cable length is less than 30m	0	0
S6	Transmission power of CH3 Setting 1 = default Setting 0 = reduction if when using plastic fiber optic cable on CH3 an overload occurs or if the fiber optic cable length is less than 30m	0	0
S7	Switch on or off function compatibility with devices of the previous generation SINEC L2FO OLM / P3, -P4, -S3, -S4, S3-1300 and S4-1300.	0	0
S8	Operating mode of the electrical channel CH0 Setting 0 = electrical channel with segment monitoring Setting 1 = electrical channel without segment monitoring Note For all OLMs that are connected to the electrical star segment CH1 / CH0 must be switched to "Monitor off" mode (S0/S8=1). This switches off the segmenting function of the RS485 channel for these OLMs in order to achieve higher availability of the electrical star.	1	1

Setting of the DIP switches for redundant optical ring
The table below shows the settings of the DIP switches on the PROFIBUS OLM V4.0 / V3 for setup of a redundant optical ring. In this example no OLMs of the previous generation SINEC L2FO OLM / P3, -P4, -S3, -S4, S3-1300 and S4-1300 are used in the redundant optical ring.
 

DIP switch	Meaning	Redundant optical ring
S0	Operating mode of the electrical channel CH1 Setting 0 = electrical channel with segment monitoring Setting 1 = electrical channel without segment monitoring	0
S1	Operating mode of the optical channel CH2	1
S2	Operating mode of the optical channel CH2	1
S3	Operating mode of the optical channel CH3	1
S4	Operating mode of the optical channel CH3	1
S5	Transmission power of CH2 Setting 1 = default Setting 0 = reduction if when using plastic fiber optic cable on CH2 an overload occurs or if the fiber optic cable length is less than 30m	0
S6	Transmission power of CH3 Setting 1 = default Setting 0 = reduction if when using plastic fiber optic cable on CH3 an overload occurs or if the fiber optic cable length is less than 30m	0
S7	Switch on or off function compatibility with devices of the previous generation SINEC L2FO OLM / P3, -P4, -S3, -S4, S3-1300 and S4-1300.	0
S8	Operating mode of the electrical channel CH0 Setting 0 = electrical channel with segment monitoring Setting 1 = electrical channel without segment monitoring	0

Additional information

• More information about PROFIBUS OLMs V4.0 is available in the manual in Entry ID: 30006392.