User guide

Operational Theory Xenus XTL User Guide
8 Copley Controls Corp.
2.2: Synchronizing PWM Switching Frequency
In some situations, such as when sampling small analog signals, it is desirable to synchronize the
PWM switching frequency among multiple amplifiers. In these cases, one amplifier serves as a
master for one or more slave amplifiers. The PWM sync output of the master sends a signal that
is received as a PWM sync input by each slave.
2.3: Commutation Modes
The amplifier supports three commutation modes to drive brush and brushless motors: AC
brushless sinusoidal, AC brushless trapezoidal, and DC brush.
In most applications, sinusoidal commutation is preferred over trapezoidal, because it reduces
torque ripple and offers the smoothest motion at any velocity or torque. In the sinusoidal
commutation mode, an encoder or a resolver are required for all modes of operation.
In AC brushless trapezoidal commutation mode, the amplifier provides traditional six-step
commutation.
When driving a DC brush motor, the amplifier operates as a traditional H-Bridge amplifier.
2.4: Feedback
2.4.1: Encoder and Resolver Support
The Xenus amplifier is offered in three versions to support encoder or resolver feedback. The
standard version supports digital quadrature encoders. The -S version supports analog sin/cos
encoders. These versions normally require the use of Hall switches for the commutation of
brushless motors. The resolver version supports standard, single speed, transmit-type resolvers.
2.4.2: Multi-Mode Port
All versions support a multi-mode port. This interface can be configured to:
• Provide a buffered digital encoder output based on the digital encoder input.
• Provide an emulated digital encoder output based on the analog encoder or resolver input.
• Provide a second digital encoder input to be used in the dual encoder position mode. In this
mode, an encoder attached to the load provides position loop feedback, and the motor
encoder or resolver provides velocity loop feedback.