Wiring the S7-400
4-14 AutomationSystem S7-400 Hardwareand Installation
A5E00850741-01
Connecting the Load VoltageGround
Many output modules require an additional load voltage to switch the actuators.
Twodifferent modes are possible for this load voltage:
•Non-isolated operation
•Floating operation
The following table shows how the load voltage ground is connected in the
individual modes.
Table4-3 Grounded connection load voltage
Mode Connectionof Load Voltage
Non-isolated operation
•Grounded configuration
•Ungrounded configuration
to the reference point of the rack; metallic connection
between frame element and chassis ground must be
fitted.
to the reference point of the rack; metallic connection
between frame element and chassis ground must be
fitted.
Floating operation
•Grounded and ungrounded
configuration
Left open or to any point, but not to protective ground
or reference potential M of operating voltages
The following figure shows how the load voltage ground is connected for
non-isolated operation.
Metallic connection, remove for
ungrounded configuration
Ground terminal for
load voltage
Figure 4-7 Grounded connection load voltage