Copley Controls Xenus R10 Manual page 157

Accelnet R21
GROUNDING CONSIDERATIONS
Power and control circuits share a common circuit-
ground (HV Gnd on J3-4, and Signal Ground on
J2-5, J4-6 & 11, J5-2,9,15,17, and 28). 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'
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 (J2-5).
Controller
Control
I/O
Equipment frame
Keep connections as close as possible.
"Star" ground to a common point is best
Copley Controls, 20 Dan Road, Canton, MA 02021, USA
Tech Support: E-mail: sales@copleycontrols.com, Internet: http://www.copleycontrols.com
The drive heatplate does not connect to any
drive circuits. Cables must be shielded for CE
compliance, and the shields should connect to the
Frame Ground terminals. When installed, the drive
heatplate should connect to the system chassis.
This maximizes the shielding effect, 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 J3. 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 heatplate to
connect it to the equipment frame ground.
Drive
Mot U
Mot V
+HV
Gnd
Frame Ground
Earth
= SHIELDED CABLES REQUIRED
FOR CE COMPLIANCE
RUGGEDIZED DIGITAL
SERVO DRIVE FOR
BRUSHLESS/BRUSH MOTORS
POWER SUPPLIES
Accelnet R21 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. Distance between
this capacitor and the drive should be 1 metre
or less.
AUXILIARY HV POWER
Accelnet R21 has an input for AUX HV. This is a
voltage that can keep the drive communications
MOTOR
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
Power
voltage range of the drive and powers the DC/DC
Supply
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.
Keep as short
as possible
MOUNTING & COOLING
Accelnet R21 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.
Tel: 781-828-8090
R21
RoHS
Fax: 781-828-6547
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