Siemens SIMATIC NET PROFIBUS Owner's Manual page 379

6ZB5530–3AC30–0BA1 Infrared Link Modul (ILM)
If the device is at the start or end of an electrical PROFIBUS segment, you must seal one threaded cable inlet
using the accompanying sealing plug.
If the mechanical stress on the PROFIBUS cable is liable to change, make sure that you install additional strain
relief. The cable clamp in the device itself is only intended for low-resistance discharge of spurious voltages on
the shield. The threaded cable inlet is used only for sealing the cable entry and to prevent the cable being
pulled out accidentally. Neither of these, however, is intended as strain relief against continuous tensile stress
on the cables.
37
Copyright by Siemens