Network Topologies
3.2 Star Topology
SIMATIC NET PROFIBUS, Optical Link Module
Operating Instructions, 07/2008, A2B00065774O, Edition V1.5
11
When the monitoring on the optical channels is active, the fiber-optic links are
monitored by the connected OLMs.
Note:
Unused optical channels you intend to use later to expand the network cause a
broken fiber-optic cable signal if the monitoring is active. You can avoid this error
message by setting unused channels to the mode
“
bus without fiber-optic link
monitoring”. Remember that the optical channels that are not connected must be
protected against external light and pollution by protective caps.