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Positioning controllers can handle dynamic motors
Published:  16 April, 2014

The Swiss small motor specialist maxon motor has announced a compact EtherCat slave controller which, it says, offers “unprecedented possibilities as far as precision, dynamics, and synchronization are concerned”.

In the past, in particularly demanding applications, controllers have sometimes had difficulty coping with the highly dynamic capabilities of maxon’s ironless DC brushed motors and brushless motors. Maxon says that the new Maxpos 50/5 motion controller allows the motor’s properties to be utilised fully.

The controllers use FPGA (field programmable gate array) technology to achieve high control cycle rates with short cycle times. When used for trajectory planning with a suitable EtherCat master, they can perform sophisticated motion control tasks with current controller clock speeds of 100kHz and effective communication cycle times of 100µs.

The controllers support distributed clocks as well as CoE (CAN-over-EtherCat) with cyclic synchronous modes. Profile-based position and velocity operating modes are also available. The substantial processing power allows field-oriented sinewave commutation of brushless motors up to 200,000 rpm.

A variety of feedback options allow the use of a wide range of permanent magnet DC motors with encoders, and brushless motors with digital Hall sensors and encoders, in ratings up to 250W. Encoders supported include digital incremental devices, analogue sine-cosine incremental types, and absolute encoders with SSI, EnDat2.2 or BiSS-C interfaces.

maxon's new-generation controllers support highly dynamic motors

Two different encoders can be used simultaneously, allowing for dual-loop control of a master to compensate for mechanical backlash and elasticity in the drive system.

The positioning controllers incorporate protection against overcurrent, high temperatures, under- and over-voltages, voltage transients, short-circuits in the motor cable, and loss of feedback signals. Motors and loads can be protected using variable current limiting.

The supply voltage range is from 10–50V DC and the output current is up to 5A continuous (15A peak).