The AS‑Interface overvoltage protection module (protection module) protects downstream AS‑Interface devices or individual sections in AS‑i networks from conducted overvoltages, which can be caused by switching operations and remote lightning strikes. The location of the protection module forms the transition from zone 1 to 2/3 within the lightning protection zone concept. Direct lightning strikes must be coped with using additional protective measures at the transitions from lightning protection zone 0A to 1.

With the AS-Interface overvoltage protection module, it is now also possible to integrate AS-Interface in the overall overvoltage protection concept of a plant or machine.

The module has the same design and degree of protection (IP67) as the AS-Interface K45 compact modules. It is a passive module and as such does not need its own address on the AS‑Interface network. The module can be used to protect the AS-Interface cable and the cable for the auxiliary voltage from overvoltage. Overvoltages are discharged through a ground cable with a green/yellow oil-proof outer sheath. This cable is fixed in the module and must be connected with low resistance to the system's ground.

Rated discharge current I_sn

The rated discharge current is the peak value of a surge current of the form 8/20 Ојs (microseconds), for which the protection module is designed in accordance with a specified test program. With an 8/20 waveform, 100 % of the value is achieved after 8 Ојs and 50 % after 20 Ојs.

Protection level U_p

The protection level of a protection module is the highest momentary value of the voltage at the terminals, established in individual tests, and characterizes the capability of a protection module to limit overvoltages to a residual level.

Configuration guidelines

Configuration guidelines for overvoltage protection modules

The grounding of protection modules and the units to be protected must be effected through a shared grounding point. If insulated devices are protected, their mounts must be included in the grounding points.

Sample application

Sample application for overvoltage protection modules