Siemens SIMATIC IPC477E Operating Instructions Manual page 42

Mounting and connecting the device
3.3 Connecting the device
NOTICE
Damage through regenerative feedback
Regenerative feedback of voltage to ground by a connected or installed component can
damage the device.
Connected or built-in I/Os, for example, a USB drive, are not permitted to supply any
voltage to the device. Regenerative feedback is generally not permitted.
42
Operating Instructions, 12/2016, A5E37455003-AB
SIMATIC IPC477E