Interfaces; Connecting The Equipotential Bonding Circuit - Siemens SIMATIC HMI OP 73micro Operating Instructions Manual

Mounting and connection
4.3 Mounting and connecting the TP 177micro
4.3.2.1

Interfaces

The figure below shows the interfaces of the HMI device.
Figure 4-12
①
②
③
See also
Power supply (Page 146)
RS 485 (IF 1B) on TP 177micro (Page 147)
4.3.2.2

Connecting the equipotential bonding circuit

Potential differences
Differences in potential between spatially separated system parts can lead to high equalizing
currents over the data cables and therefore to the destruction of their interfaces. This
situation may arise if the cable shielding is terminated at both ends and grounded at different
system parts.
Potential differences may develop when a system is connected to different mains.
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1 2 3
Interfaces of the HMI device
Chassis ground terminal
Power supply connector
RS 485 interface (IF 1B)
OP 73micro, TP 177micro (WinCC flexible)
Operating Instructions, 09/2007, 6AV6691-1DF01-0AB0