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Stepper building block aids system automation

Edited by the Engineeringtalk editorial team Jul 1, 2003

The ViX Microstep packs an advanced motion controller with either a 250 or 500VA power amplifier into an ultracompact case.

The ViX Microstep packs an advanced motion controller with either a 250 or 500VA power amplifier into an ultracompact case - providing a building block that can boost automation throughput while simultaneously reducing system size and cost.

The raw performance of the power stage is intelligently controlled using innovative new digital signal processing techniques.

Advanced field-orientated control (FOC) is applied to the digital current loop to enhance the torque-speed envelope.

This has the effect of eliminating 'midrange instability', and reducing torque ripple - leading to improved low-speed smoothness.

Furthermore, the innovative 'intelligent damping' control typically reduces settling time by up to a factor of four - significantly enhancing throughput for precision equipment OEMs.

ViX Microstep drives are packaged in the same exceptionally compact book-style housing as the ViX servo drive - measuring just 125 x 42 x 85mm - for direct panel mounting, or attachment to a standard DIN rail using an optional adapter.

The drive is available with a choice of 2.8 or 5.6A RMS output current ratings, and accommodates motor bus voltages up to 80V DC.

To ensure smooth operation at all times, the power stage operates at its full 51,200 steps per revolution resolution regardless of the actual steps per revolution programmed by users.

Moreover, the user resolution is freely programmable in the range from 400 to 51,200 steps per revolution, allowing the motion system to be matched precisely to the mechanics, even where there is an odd transmission ratio or leadscrew pitch.

The drives can be commanded directly from a PC, a centralised control system generating industry-standard step-direction signals, or optionally a fieldbus system.

In addition they will operate autonomously using motion control programs stored within their powerful built-in controller - these may be executed in response to external events, or signals from a host controller such as a PLC.

The built-in controller uses the well-proven Easi command language, and supports all standard motion control functions.

In addition, a number of advanced functions such as electronic gearing, registration, closed-loop position maintenance and stall detection are offered.

The controller is equipped with an RS232C interface as standard, and optionally a fieldbus interface for CANopen and RS485 communications.

Standard I/O facilities include five digital inputs and three digital outputs, all of which offer software-configurable termination characteristics and 5 or 24V operation.

Rapid system configuration and programming of ViX Microstep drives is achieved by using the Easi front-end software package.

This powerful Windows-based software tool makes extensive use of guided wizards and simple hierarchically structured pull-down menus to simplify configuration and programming.

When the drives are used with certain recommended stepper motors, users only need to select the motor from a menu to define the entire configuration; as all setup information is retrieved automatically from a built-in database.

The drive automatically optimises FOC control according to motor parameters that are entered either directly, or through selecting the appropriate motor model using Easi software.

This enables a wide range of motors to be accommodated without compromising performance.

The result is unsurpassed torque/speed performance, smooth and resonant-free operation at low speed, reduced torque ripple and significantly reduced settling times - permitting increased production throughput - together with improved efficiency and quieter operation.