Grounding Considerations - Copley Controls Xenus R10 Manual

Accelnet R20

GROUNDING CONSIDERATIONS

Power and control circuits in Accelnet R20 share a common circuit-ground (Gnd on J1-4,
and Signal Ground on J2-2, 10 ,15 ,20, and J3-2, 23). Input logic circuits are referenced
to Signal Ground, as are analog Reference inputs, digital outputs, encoder and Hall signals.
For this reason, drive Gnd terminals should connect to the users' common ground system
so that signals between drive and controller are at the same common potential, and to
minimize noise. The system ground should, in turn, connect to an earthing conductor at
some point so that the whole system is referenced to "earth". The CAN ports are optically
isolated from the drive circuits.
Because current flow through conductors produces voltage-drops across them, it is best
to connect the drive HV Return to system earth, or circuit-common through the shortest
path, and to leave the power-supply floating. In this way, the power supply (-) terminal
connects to ground at the drive HV Return terminals, but the voltage drops across the
cables will not appear at the drive ground, but at the power supply negative terminal
where they will have less effect.
Motor phase currents are balanced, but currents can flow between the PWM outputs, and
the motor cable shield. To minimize the effects of these currents on nearby circuits, the
cable shield should connect to Gnd (J1-4).
The drive case does not connect to any drive circuits. Connections to the case are provided
on connectors J2-1, and J3-1. Cables to these connectors should be shielded for CE
compliance, and the shields should connect to these terminals. When installed, the drive
case should connect to the system chassis. This maximizes the shielding effect of the case,
and provides a path to ground for noise currents that may occur in the cable shields.
Signals from controller to drive are referenced to +5 Vdc, and other power supplies in
user equipment. These power supplies should also connect to system ground and earth
at some point so that they are at same potential as the drive circuits.
The final configuration should embody three current-carrying loops. First, the power supply
currents flowing into and out of the drive at the +HV and Gnd pins on J1. Second the
drive outputs driving currents into and out of the motor phases, and motor shield currents
circulating between the U, V, and W outputs and Gnd. And, lastly, logic and signal currents
connected to the drive control inputs and outputs.
For CE compliance and operator safety, the drive should be earthed by using external tooth
lockwashers under the mounting screws. These will make contact with the aluminum chassis
through the anodized finish to connect the chassis to the equipment frame ground.
Copley Controls, 20 Dan Road, Canton, MA 02021, USA
Tech Support: E-mail: sales@copleycontrols.com, Internet: http://www.copleycontrols.com
= SHIELDED CABLES REQUIRED
FOR CE COMPLIANCE
RUGGEDIZED DIGITAL
SERVO DRIVE FOR
BRUSHLESS/BRUSH MOTORS
POWER SUPPLIES
Accelnet R20 operates typically from
transformer-isolated, unregulated DC
power supplies. These should be sized such
that the maximum output voltage under
high-line and no-load conditions does not
exceed the drives maximum voltage rating.
Power supply rating depends on the power
delivered to the load by the drive. In many
cases, the continuous power output of the
drive is considerably higher than the actual
power required by an incremental motion
application.
Operation from regulated switching power
supplies is possible if a diode is placed
between the power supply and drive to
prevent regenerative energy from reaching
the output of the supply. If this is done,
there must be external capacitance between
the diode and drive.
Accelnet
Amplifier
AUXILIARY HV POWER
Accelnet R20 has an input for AUX- HV.
This is a voltage that can keep the drive
communications and feedback circuits
active when the PWM output stage has been
disabled by removing the main +HV supply.
This can occur during EMO (Emergency Off)
conditions where the +HV supply must be
removed from the drive and powered-down
to ensure operator safety. The AUX HV input
operates from any DC voltage that is within
the operating voltage range of the drive and
powers the DC/DC converter that supplies
operating voltages to the drive DSP and
control circuits.
When the drive +HV voltage is greater than
the AUX-HV voltage it will power the DC/DC
converter. Under these conditions the AUX-
HV input will draw no current.
MOUNTING & COOLING
Accelnet R20 has slots for mounting to
panels at 0° or 90°. Cooling is by conduction
from drive heatplate to mounting surface,
or by convection to ambient.
A heatsink (optional) is required for the
drive to deliver the rated continuous
output current. Depending on the drive
mounting and cooling means this may not
be required.
Tel: 781-828-8090
R20
RoHS
+HV
(+)
Switching
Power
Gnd (-)
Supply
Fax: 781-828-6547
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