Drive for brushless DC servo motor motion control

New version of drag-and-drop flowchart programmed motion controller with integral servo drive opens market with low-cost brushless servo version

Since its launch in early 2009, Rotalink's Red Drive servo motor driver and controller has significantly lowered the cost barrier for brushed DC precision motion control. Now the innovative designer and manufacturer of miniature motors, transmissions and controls has launched a brushless version of Red Drive that offers the same easy-to-use flowchart based software and price-performance advantages of the brushed version. The new BLDC10A Brushless Red Drive has a 10A input current rating from a 12-24 VDC supply voltage and includes hall sensor inputs for brushless commutation, incremental encoder input and 27 programmable TTL level I/O pins for analogue and digital machine interfacing.

Like its brushed servo counterpart, the modular design concept includes the separately supplied SA1 serial port adapter to program the controller with the free-of-charge Red Drive PC-based graphical software. For fast and cost-effective OEM product development, the microprocessor chip is available separately, allowing the full board version with its integral servo drive to be used in the design and pre-production phases with the IC version incorporated in the final machine for full production. This option also enables the customer the flexibility to choose and design-in the optimum power components and I/O requirements for the application.

This drive is easy to program using a drag and drop flowchart programming method which eliminates the complexity typically associated with many other motion controllers available today. The Windows™ program allows scaling of encoder and gearbox resolution into meaningful units at set-up along with I/O interfacing assignment. Set-up also includes simply entering catalogue values for motor stall-torque and no-load speeds for automatic tuning. Homing, limits and reset inputs can also be set.

The sequential graphical programming format requires little training or specialist motion control knowledge. The programmer simply creates then drags and drops function blocks in a sequential order with relevant values. Separate subroutines can be included in the program to call specific functions at any time on input states or as a part of the program flow. Program functions include incremental and absolute distance moves, acceleration, speeds and wait times in addition to maths and variable calculations. In all, the Red Drive's EEPROM memory storage can handle repeatable sequences of more than 100 functions and drives may be easily linked through I/O for multi-axis set-ups. An A safety input may also be configured to shutdown the drive for emergency measures.

Up to 8 of the 27 I/O points may be assigned to 5V analogue inputs with the remaining available for digital I/O interfacing at 5V TTL levels. All I/O is connected to the BLDC10A via a IDC type connectors using space saving flat cable assemblies or crimp connectors with standard wiring. The 4-pin encoder connection uses a snap-lock header connector, and motor, power and hall sensor connection is via convenient screw terminals. The SA1 RS232 serial adapter board is interfaced via a 14-way header and only needs to be connected to the drive when programming and is therefore useful for production environments or security minded OEM applications where access needs to be restricted.

New DC motors

Rotalink has launched a range of high-torque brushed DC motors with neodymium rare earth magnets. The new RE series delivers at least twice the maximum shaft power of similar sized permanent magnet DC motors and are a cost effective option where increased dynamic performance and/or small size are important application factors. The low cogging design uses very thin and lightweight neodymium magnets with high density windings and a 6-slot core for smooth motion and an excellent torque to inertia ratio.

The long life RE series motors are available in diameters of 15, 24 and 30mm with nominal voltages of 12 and 24 VDC. Through the range, maximum motor power is from 2.0 W to 29 W and maximum stall torque from 9 to 299 mNm.

These new motors are sourced from global distribution partners as a part of their strategy to maintain competitive pricing for commodity components and combine them with its own innovative designs for gearbox, motor feedback and motion control technologies to enable low-cost miniature rotary power transmission solutions up to 28 Nm and linear motion solutions to 50 N.

Their range includes planetary and spur gearbox designs that feature a selection of standard or enhanced polymer gears on sintered or ball bearings in a wide choice of output torque ratings. The range also includes unique ovoid style gearboxes that combine spur gears with ultra-polymer planetary stages for extremely high torque output in very compact designs. This flexibility allows customers to exactly match their performance requirements from motor type through to performance characteristics without compromising cost.

They also manufacture incremental and absolute encoder feedback devices along with speed controls and innovative motion controls including Red Drive - a powerful DC motor drive with drag-and-drop flow chart programming for motion control including encoder feedback for motors up to 200 Watts.
The RE series motors are included in Rotalink's new and revised full range catalogue which includes two other new DC motor ranges ( heavy case and brushless) in addition to several new gearbox lines and new absolute encoders, and a brushless version of Rotalink's Red Drive motion controller.

Mini motors, power transmission & controls

New catalogue covers three additional DC motor technologies, a new brushless drive and increased resource material for miniature power transmission mechanics and controls

A new and revised full range catalogue from Rotalink includes several new products and additional technical information aimed at making an informed selection for highly cost competitive miniature power transmission systems and controls. The new resource covers performance specifications for three recently added DC motor technologies (rare earth, heavy case and brushless) as well as several new gearbox lines along with a completely new section on DC motor control - including new absolute encoders and a brushless version of Rotalink's flagship motion controller, Red Drive.

The new catalogue reflects just how busy the company has been over the past two years - developing and improving a complete range that allows its customers the benefit of volume sourced and low-cost DC, AC and stepper motor technologies from global partners which are integrated with in-house designed and manufactured miniature gearboxes, motor feedback components and motion control technologies.

Rotalink's strength and expertise lies in adapting advanced materials technologies into its own innovative designs for miniature gearbox and associated components to realise leading-edge and cost effective solutions for miniature power transmission systems up to 28 Nm torque and to 150 W shaft power. With its own manufactured range of planetary and ovoid style gearboxes that include a flexible choice standard or enhanced polymer gears with sintered or ball bearings, it is possible to exactly match a customer's specification without cost compromise. Furthermore, the choice of advanced materials and their unique ovoid gearboxes with spur/planetary output stages can yield extremely high torque in space restricted envelopes and are a perfect solution where miniaturisation in design or maximising power to size is of prime importance.

By adapting these same gearbox designs with their space saving incremental or absolute encoder feedback devices, and by adding speed or positional motion control, Rotalink provide a complete single-source service for miniature linear or rotary power transmission systems at costs which are much less than its competitors.

The new catalogue includes complete specification information for three recently introduced DC motor technologies; high power brushed DC motors with neodymium rare earth magnets, heavy case low inertia brushed DC motors, and low cost brushless DC motors complete with hall effect sensors for commutation.

Also, recently launched and available for the first time in the new catalogue is a brushless version of the Red Drive programmable motion controller for up to 10A output from a 12 – 24 VDC source with up to 27 configurable analogue and digital I/O points for comprehensive machine control interfacing.

For each of the DC, AC and Stepper motors section in the new catalogue, a detailed selection guide is included with technical assistance information available such as countermeasures for EMI and a discussion on customisation options for DC motor gearbox applications. Engineers and designers involved in miniature power transmission systems will find Rotalink's new catalogue an invaluable resource.

It may be downloaded in pdf format from their website.