Application Notes
170
Atlas® Digital Amplifier Complete Technical Reference
B
B.2
DC Brush & Step Motor Atlas with
Multi-Axis Magellan
The following schematic shows a two-axis application with one DC Brush Atlas Amplifier and one step motor Atlas
amplifier controlled by a multi-axis Magellan.
B.2.1
Atlas Power Input and Motor Output
Atlas is powered through pin pairs HV and Pwr_Gnd, and the power source is a transformer-isolated DC power
supply. In this application the two Atlases share the same power supply. Alternatively they could be powered
independently so that different motor voltages could be used.
For DC Brush motors pins MotorA and MotorB are wired to motor windings Motor+ and Motor-, respectively. Pins
MotorC and MotorD are left un-connected.
For step motors pins MotorA, MotorB, MotorC and MotorD are wired to motor windings A+, A-, B+ and B-,
respectively.
Please refer to B.1 for layout and wiring recommendations on power input and motor outputs.
B.2.2
Atlas SPI Interface
Atlas receives control commands through an SPI interface and functions as an SPI slave. Atlas SPI communication is
enabled when ~SPICS is pulled down. Only one Atlas can be enabled at any given time.
Please refer to B.1 for layout recommendation on SPI interface.
B.2.3
Atlas ~Enable and FaultOut Signals
Atlas has one dedicated input signal, ~Enable, which must be pulled low for the Atlas output stage to be active.
FaultOut is a dedicated output. During normal operation it outputs low. When a fault occurs it will go into a high
impedance state. In this example, FaultOut is pulled up by Vpullup through resistor R1. Vpullup can be up to 24V to
meet the system requirement. Each Atlas may use a different Vpullup voltage, for example, if the fault signal is wired
to a 5V TTL input, Vpullup can be 5V.
B.2.4
Magellan MC58420 Configuration
In this schematic the SPI master is a four-axis Magellan MC58420. Only the connections with Atlas are shown. For
complete Magellan wiring, please refer to the MC58420 electrical specifications.
The MC58420 is configured to default to Atlas motor output by tying pin 7, OutputMode0, to ground. In this example
axis 2 and axis 3 are under control. The MC58420 sends torque commands to the DC Brush Atlas by pulling
SPIEnable2 low, and sends position commands to the step motor Atlas by pulling SPIEnable3 low.
