BRA Servo Drive
  • 20-150VDC 20A brushed DC servo drive.
  • Single or dual encoder operation.
  • Unprecedented trajectory following accuracy.
  • Easy tuning with free Tuna™ software for Windows.
  • Real-time statistical position error analysis.
  • Silent, cool running operation.
  • Exact position stop, no dithering or hunting.
  • Intelligent limit switch support.
  • Unlimited electronic gearing of encoder/step resolution.
  • 20 LED indicators on I/O lines, power, status and alarms.
  • Fully isolated control circuitry.
  • Dual 32-Bit ARM CPUs.
  • Latest design and control algorithms for 2017.
  • Free worldwide shipping. Money-back Guarantee.
  • Designed and manufactured in Australia to IEC/EN 61800-5-1.
AUD $299 in stock


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Dual Encoder Support

  • Supports single or dual incremental encoder operation up to 2MHz count rate.
  • Supports single ended or differential encoder types . True differential operation with RS485 standard line driver chips.
  • All encoder inputs are isolated from power circuitry.
  • User adjustable digital noise filtering.
  • High efficiency DC-DC converter provides up to 250mA per encoder at 5V.
  • Extremely high positional accuracy in dual encoder mode. Typical results are point-to-point positioning error < ±0.5 encoder counts and < ±1.5 encoder counts full trajectory tracking error at the tool, measured as per ISO 230-2 ±2 Sigma error deviation.

Advanced Control Algorithms

  • Supports modified PI-D (PIV) algorithm for single encoder, and modified cascade algorithm for dual encoder.
  • Dedicated 32 bit ARM control board CPU with double precision floating point motion calculations.
  • Command velocity improvement with glitch filter, sliding filter and noise filter.
  • Frequency and 1/T command velocity estimation with automatic transition.
  • Velocity and acceleration feed forward with time shifting.
  • Stiction and reversal compensation.
  • Fast settle feature stops dead on exact encoder count without dithering or deadband.
  • Supports all combinations of metric and imperial hardware. Automatic calculation of electronic gearing and step multiplying with no loss of precision.
  • Abnormal condition detection like saturation, following error and encoder fault.

Easy Setup and Operation

  • Standard step and direction input supports popular CNC programs like Mach3.
  • All control signals are isolated from power circuitry.
  • Easy drive commissioning with free Tuna software for Windows via USB.
  • 20 LED indicators show all I/O states without multimeters or oscilloscopes.
  • In-built waveform generator creates tuning waveforms such as trapezoid and S-profile.
  • Easy parameter configuration. Real-time adjustment while tuning.
  • Eight channel scope with pan and zoom for easy waveform analysis.
  • Digital readouts on command, motor and load positions.
  • Real time statistical position error analysis and charting over multiple time intervals.
  • Assign drive axis names and connect multiple drives simultaneously.

Advanced Power Stage

  • DC bus voltage from 20 to 150VDC. Under and over voltage monitoring and alarms. User adjustable current limit from 5 to 20A. Current limiting alert.
  • High efficiency MOSFET bridge with low Rds ON resistance. Typical applications require no additional heatsink or cooling.
  • Dedicated 32 bit ARM CPU for power stage.
  • Silent operation. No singing or dithering.
  • Optional power saving mode significantly reduces drive and motor losses with no effect on performance.
  • Dual di/dt output filter inductors reduce EMI and increase SOA under fault conditions.
  • Four quadrant short circuit detection protects against motor to motor, motor to negative and motor to positive supply faults.
  • Progressive overload protection shuts down within 0.4mS to 2 sec depending on severity of overload condition, while eliminating nuisance tripping.
  • Snubber circuits across each MOSFET for reduce di/dt and switching stress. Additional snubbers on motor power rails.
  • Independent thermal monitoring of heat sink, output inductors and main filter capacitors with audible warning and shutdown.
  • High efficiency DC-DC converter supplies power stage with negligible losses and spread-spectrum frequency for reduced EMI.
  • Power stage is isolated from control circuitry and earth.

Limit/Home Switch Support

  • Supports direct connection of mechanical switches or NPN inductive proximity switches.
  • Supports normally open (NO) or normally closed (NC) operation.
  • Limit switch inputs are isolated from power circuitry.
  • Intelligent jogging off limits, but not into them.
  • Homing off limit switches or combined with encoder index pulse for precise homing to within 1 encoder pulse.
  • User adjustable digital noise filtering.


Stepper Drive

The entire system is open loop. Position error is made up of the following:

  • Stepper motor construction accuracy.
  • Missed steps.
  • Loose wires, intermittent connection.
  • EMI interference pickup.
  • Coupling flex and slip.
  • Thrust bearing deflection.
  • Ballscrew/belt/rack pitch error.
  • Ballscrew torsion/belt stretch.
  • Ballnut play, pulley pitch error.
  • Backlash.
  • Drive train wear.
  • Stiction, friction.
  • Thermal expansion.

Servo Drive

The motor position is closed loop. Drivetrain is open loop. Position error is made up of the following:

  • Motor encoder accuracy.
  • Coupling flex and slip.
  • Thrust bearing deflection.
  • Ballscrew/belt/rack pitch error.
  • Ballscrew torsion/belt stretch.
  • Ballnut play, pulley pitch error.
  • Backlash.
  • Drive train wear.
  • Stiction, friction.
  • Thermal expansion.

Dual Encoder Drive

The entire system is closed loop. Position error is made up of the following:

  • Glass scales accuracy.

Typical results are point-to-point positioning error < ±0.5 load encoder counts and < ±1.5 load encoder counts full trajectory tracking error at the tool, measured as per ISO 230-2 ±2 Sigma error deviation.

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