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Ground (Earth) Design
IMS-MN-LMDE42C_A
Liberty MDrive Ethernet TCP/IP
The following graphic illustrates system power wiring.
+VDC GND
+VDC Supply
12V - 48V
AUX GND
AUX Supply
12V - 24V
Ground (Earth) Design
The ground (earth) connections of all interfaces are connected, including the ground for the
VDC supply voltage.
The exception to this is the logic ground connection of the I/O interface, which is optically
isolated.
The following points must be considered when wiring the drives in a system:
• The voltage drop in the
VDC
power supply lines must be kept below 1 V. At higher ground
potential differences between different drives, the communication and control signals may
be affected.
• For larger distances between system components, the use of decentralized power supply
units located close to the individual drives may be needed to supply
DC
voltage. The ground
connections of the individual power supply units must be connected with the largest possible
conductor cross section.
• If the master controller (e.g., PLC, industrial PC, etc.) does not have galvanically isolated
outputs for the drives, verify that the current of the
DC
supply voltage has no path back to
the power supply unit via the master controller. Therefore, the master controller ground may
be connected to the
DC
supply voltage ground at a single point only. This is usually the case
in the control cabinet. The ground contacts of the various signal connectors in the drive are
therefore not connected; there is already a connection via the
DC
supply voltage ground.
• If the controller has a galvanically isolated interface for communication with the drives,
the ground of this interface must be connected to the signal ground of the first drive. This
ground may be connected to a single drive only to avoid ground loops.
