1 point–to–point–link – Siemens SIMATIC NET PROFIBUS User Manual

Page 353

Infrared Link Modul (ILM)

6ZB5530–3AC30–0BA1



by Siemens

5.2.1

Point–to–Point–Link

Infrared
transmission link
0.5 to 15 m

PROFIBUS
master network segment

PROFIBUS
slave network segment

Slave

Master

Slave

ILM

Figure 2:

Point-to-Point Link with Two PROFIBUS ILMs

Figure 2 describes the typical layout of a PROFIBUS network with master and slave nodes and an infrared
transmission link with two PROFIBUS ILMs. The infrared transmission link is implemented as a point-to-point
link by the two PROFIBUS ILMs. In this situation, the two PROFIBUS ILMs replace a cable connection
between the two network segments. Remember that only slave nodes are permitted in the slave network
segments.

Make sure that the terminating resistors are activated at the segment ends (either in the bus
connector or in a PROFIBUS ILM).

Cascading is a further application for a point-to-point link.

Note

This “cascading with PROFIBUS ILM” mode is possible, but does involve a risk when operating PROFIBUS.
The transmission using an infrared link is generally more susceptible to problems than transmission via cable
(optical or electric).