Aerotech has launched a digital servo amplifier with a linear power stage for ultra-high-resolution brushed or brushless linear and rotary motion control systems.
The new compact ML series amplifier is intended for lower-power use but maintains the high-performance characteristics required for nanometre and micro-radian-level precision positioning applications that are acutely susceptible to electrical noise and where pulse-width-modulation (PWM) servo amplifiers become unusable.
The DSP-based ML range is designed for minimal radiated noise to allow the servo system to provide high levels of speed control and in-position stability for ultra-smooth motion profiles and to ensure negligible interference levels for sensitive processing and measuring equipment.
Aimed at high-resolution motion system applications as found in non-destructive testing (NDT), micro-electromechanical systems (MEMSs), vision systems and microscopy but with less dynamic performance requirements, the new amplifier is available in three versions: as the Ndrive ML option for Aerotech's A3200 software-only motion controller; as an entry-level version of the Soloist ML integrated single-axis position controller range; and as a low-cost linear drive stage solution for the multi-axis Ensemble ML, a networkable and panel-mount motion control system.
The basic specifications for the ML series linear amplifiers in all configurations include a 5A continuous/10A peak current rating with a customer-supplied DC bus voltage of +/-40V and a control supply requirement of 18-36VDC.
A single 16-bit +/-10V analogue input is used for direct interfacing to the motion controller, with an Estop sense input included.
The ML features primary and secondary incremental encoder interfaces that are optionally equipped with Aerotech's MXH hardware-based multiplied encoder technology for up to 65,536 times quadrature output.
Using a 1V p-p sinusoidal encoder that does not require a costly power supply, this level of multiplication has a 2MHz analogue input frequency that allows nanometre or micro-radian-level resolution across Aerotech's range of high-precision direct-drive positioning mechanics.
The MXH encoder option also enables the single-axis Position Synchronised Output (PSO) feature to be implemented at a high level.
The PSO is a algorithmic software tool that precisely co-ordinates the real-time position from a linear or rotary encoder with high-speed output pulses from the controller that are used to trigger external events.
This feature is used in applications such as laser micromachining or position-critical NDT, where exacting, no-compromise synchronisation is required between laser firing or sensor reading and the axis path position.
For the alternative software-based MXU encoder version, the encoder interfaces have a 4,096 multiplication factor and both MXU and MXH encoder options include end-of-travel limits and home inputs on the primary feedback encoder.
An optional input/output (I/O) expansion board is also available to equip the ML drive with eight opto-isolated digital inputs and eight digital outputs (sinking or sourcing) in addition to single 16-bit analogue I/Os and a brake relay output.
As the ML series linear stage amplifier does not include an integrated power supply and the I/O expansion option may not be required for some applications, the drive can be a low-cost solution and its small footprint may be advantageous in space-restricted OEM applications.
The ML drive's 10A peak current rating will provide sufficient power for the majority of micro-positioning applications.
However, where more useful power may be required and in areas where amplifier temperature rise must be kept to a minimum, a water-cooled version is available.
This version can provide a 35 per cent increase in usable power.
In addition to the ML range, Aerotech also produces linear-stage amplifiers with two- and three-axis PSO capabilities, integral mains-power supplies and built-in I/O and fieldbus interfaces - offering the excellent linearity, high bandwidth, zero crossover distortion and ultra-quiet EMC characteristics of the ML series.
These control options and higher-power versions are available throughout the A3200, Soloist and Ensemble ranges and the company also offers a full complement of PWM-stage amplifiers for high-speed and heavy-load precision positioning applications.
All of these Aerotech drive technologies may be freely mixed for multi-axis positioning systems.
A choice of PC-based software-only or rack- or panel-mounted motion controls in single- or multi-axis formats allows optimal performance with diagnostics and comprehensive features that are intended to ensure fast product development and commissioning, reduce positioning errors, improve throughput performance and ensure time-saving and quality-improving benefits, according to the company.
