Siemens SIMATIC ET 200S Manual page 577

Special Measures for Interference-Free
Operation
Inductive voltages
Overvoltage occurs when sources of inductance are switched off. Examples of this
are relay coils and contactors.
Integrated overvoltage protection
The digital output modules of the ET 200S have an integrated overvoltage
protection device.
Additional overvoltage protection
Inductance can only be wired with additional overvoltage protection devices in the
following cases:
• If digital output circuits can be switched off by additionally installed contacts,
such as relay contacts.
• If the inductance cannot be controlled by digital output modules.
Note: Request information on relevant surge protection rating from the supplier of
inductive devices.
ET 200S Distributed I/O System
EWA-4NEB 780602402-12
F
F-1