Operating instructions

Active Components and Topologies
6-5
SIMATIC NET Tw isted-Pair and Fiber-Optic Networks
C79000-G8976-C125-02
6.1.1 Components of the Product
SIMA TIC NET Industrial Ethernet OLM/ELM including
S Terminal block for the power supply
S Description and operating instructions
Order number
SIMA TIC NET Industrial Ethernet OLM 6GK1102-4AA00
SIMA TIC NET Industrial Ethernet ELM 6GK1102-5AA00
6.1.2 I nstallation
The SIMATIC NET Industrial Ethernet OLM/ELM is clipped on to a standard rail.
The modules can be installed vertically one beside the other without gaps.
Unobstructed convection of the surrounding air must be assured, in particular, air
must be able to circulate through the ventilation openings at the top and bottom.
6.1.3 Description of the Functions
6.1.3.1 General Functions
Signal Regeneration
The OLM/ELM regenerates the signal shape and amplitude of the received data.
Retiming
To prevent jitter increasing from segment to segment, the OLM/ELM retimes the
data to be transmitted.
Preamble Regeneration
If preamble bits of received data are lost, the OLM/ELM pads out the preamble to
64 bits (including the start of frame delimiter (SFD)).
Fragment Extension
Short fragments can result from collisions. If the OLM/ELM receives a fragment,
this is extended to a minimum length of 96 bits. This ensures reliable collision
detection by all nodes.