Installing and connecting the device 
  3.3 Connecting the device 
SIMATIC IPC547D 
Operating Instructions, 06/2011, A5E03473780-01 
31 
CAUTION 
 
Fault caused by I/O devices 
The connection of I/O devices can cause faults in the device. 
The result may be personal injury and damage to the machine or plant. 
Note the following when connecting I/O devices: 
  Read the documentation of the I/O devices. Follow all instructions in the documentation.
  Connect only I/O devices which are approved for industrial applications in accordance 
with EN 61000-6-2/IEC 61000-6-2.  
  Peripheral devices that are incapable of hot-plugging may only be connected after the 
device has been disconnected from the power supply. 
 
CAUTION 
 
Damage through regenerative feedback 
Regenerative feedback of voltage to ground by a connected or installed component 
destroys 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. 
 
3.3.2  Connection of equipotential bonding 
A low-impedance earth connection ensures that interference signals generated by external 
power supply cables, signal cables or other cables to the I/O devices are safely discharged 
to earth. 
The equipotential bonding connection on a device has a large surface and makes contact 
over a large area. The equipotential bonding connection is identified by the following symbol:   
 
Requirement 
●  T20 screwdriver