Improving Smoothness & Accuracy in Stepper Systems

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Applied Motion Products Improving Smoothness and Accuracy in Stepper Systems Presentation Oct. 2007

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Improving Smoothness and Accuracy in Stepper Systems Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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High Performance Stepper Drives from Applied Motion Products Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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About Applied Motion { Founded in 1978 { Privately Owned { Headquarters in Watsonville, CA { 30 Employees Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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About Applied Motion { Visit us on the web at http://www.applied-motion.com Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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About Applied Motion { Motors from Asia z We partner with motor manufacturers in Japan, China, and Taiwan. z Our oldest partner, Tamagawa Seiki in Japan, has been our partner for almost 30 years. Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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About Applied Motion { Drives from the U.S.A. z We research, develop, and design all of our drive electronics. z We recently formed a joint venture with Shanghai Moons’ Motor Co. to develop new motor & drive products. Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Products { We offer a wide range of Step Motors, Servo Motors, and Drives Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Today ’s Discussion { Applied Motion steppers drives improve upon two aspects of step motor system performance z Smoothness - by eliminating resonance z Accuracy - by closing the position loop Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Inherent Problem { Resonance z Step motors are resonant because in short their rotors behave much like a classic “mass on a spring”. Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Inherent Problem { Resonance z When a step motor takes a step, the rotor reacts to the changing stator field in the same way a mass on a spring reacts to a change in position. Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Inherent Problem { Resonance z Just like the mass on a spring, the motion of the rotor settles into position after each step. z This settling can last as long as a second or more in worst cases! Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Inherent Problem { Resonance z If the settling doesn’t occur rapidly, or the ringing of the rotor gets worse, the motor can become unstable and lose position (stall). Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Inherent Problem { Resonance z There are two major, negative side effects of resonance. { Rough motion { Loss of torque, which can lead to loss of position Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Inherent Problem { Resonance z Rough motion { When step motors resonate they generally vibrate excessively. { This can be bad for sensitive equipment. Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Inherent Problem { Resonance z Loss of torque { When step motors resonate much of the torque available in the motor is used up in keeping the rotor synchronized with the stator field, and in worst cases the motor will not have enough torque to move the load. { Loss of torque often leads to stalling. Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Solution { Resonance z There are three main remedies for resonance. { Microstepping { Torque Ripple Smoothing { Electronic Damping Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Solution { Microstepping z Microstepping does not eliminate the natural resonant frequency of a step motor, but it does diminish the level of excitation. z In other words, smaller steps mean smaller responses. coarse steps microsteps Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Solution { Microstepping z Stepper drives from Applied Motion can microstep even when the control signal is low resolution. z This is called Microstep Emulation. coarse steps from external indexer microstep emulation performed by drive Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Solution { Torque Ripple Smoothing z Torque ripple smoothing reduces the inherent torque ripple that all step motors display at low speeds (typically well under 5 rps). z Torque ripple smoothing works by applying a “negative” current to the motor which offsets the torque ripple. torque ripple negative current Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Solution { Electronic Damping z Electronic damping remedies two aspects of the motor’s resonance. { Inherent resonant frequencies of the motor. { A complex interaction between drive and motor that happens at higher speeds, often called “mid-band resonance”. Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Solution { Electronic Damping z The end result of electronic damping is to minimize and even eliminate the resonant response of the step motor over a wide range of speeds. with ut electronic damping Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Solution { High performance stepper drives from Applied Motion offer… z Microstep Emulation z Torque Ripple Smoothing z Electronic Damping { All of which contribute to… z Smoother motion from your step motor Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Inherent Problem { Accuracy - Open Loop Systems z When properly sized an open loop step motor system can be adequately accurate for most applications. z Keys to proper sizing are knowing the load and knowing the move parameters ahead of time. z However, the nature of an open loop system is such that no built-in mechanism exists for indicating a motor mis-position or stall. Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Solution { Accuracy - Open Loop z In situations where an extra layer of accuracy is required, step motors from Applied Motion can be fitted with high resolution, incremental encoders. z The encoder is mounted to the rear shaft of the step motor (order “D” option). Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Solution { Accuracy - Open Loop z The encoder is then connected to the drive via a feedback cable. Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Solution { Accuracy - Open Loop z Applied Motion stepper drives can perform two main functions when an encoder is added to the system. { fool-proof Stall Detection { Stall Prevention w/ Position Maintenance Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Solution { Fool-proof Stall Detection z Stall detection works when the stepper drive monitors encoder position relative to commanded motor position. z As soon as a mis-position occurs the drive stops motion and sets a fault to notify the user. z This method is fool-proof because it works under all conditions, regardless of motor speed or load conditions. Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Solution { Stall Prevention z Like stall detection, Stall Prevention works when the stepper drive monitors encoder position relative to commanded motor position. z As soon as a lag between the encoder position and the commanded motor position occurs the stepper drive starts to slow the motor speed. Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Solution { Stall Prevention z Slowing down the motor allows the motor to operate in a speed range where its torque output is higher, and therefore have a better chance of finishing the move. Point at which torque demand increases Actual Move Profile Target Move Profile with Stall Prevention TargetTime Actual Time Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Solution { Position Maintenance z With Stall Prevention turned on the drive automatically corrects errors in motor position from external forces when the motor is at rest. z In other words, if the motor is “bumped” out of position it automatically corrects itself. Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Solution { High performance stepper drives from Applied Motion offer… z Encoder feedback options { Which contribute to… z A more accurate motion control system Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Hardware { High Performance Stepper Drives from Applied Motion z ST Series z STAC6 Series Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Hardware { ST Series: Two power ranges z ST5 { 5 A/phase (peak) { 24-48 VDC input z ST10 { 10 A/phase (peak) { 24-80 VDC input Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Hardware { ST Series: Three levels of control z -S { Step & Direction { Oscillator { Host command execution (SCL) { SiNet Hub compatible z -Q { Drive with built-in motion controller z -Si { Drive with built-in indexer Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Hardware { ST Series: -S models z ST5-S z ST10-S { Microstep Emulation { Torque Ripple Smoothing { Electronic Damping { Small size Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Hardware { ST Series: -Q models z ST5-Q z ST10-Q { Microstep Emulation { Torque Ripple Smoothing { Electronic Damping { Encoder feedback option Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Hardware { ST Series: -Si models z ST5-Si z ST10-Si { Microstep Emulation { Torque Ripple Smoothing { Electronic Damping { Encoder feedback option Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Hardware { STAC6 Series: High power drive z 6 A/phase (peak) z 160 VDC bus z 110 or 220 VAC input z UL recognized (110 VAC) Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

PowerPoint Presentation:

Hardware { STAC6 Series: Three levels of control z -S { Step & Direction { Oscillator { Host command execution (SCL) { SiNet Hub compatible z -Q { Drive with built-in motion controller z -Si { Drive with built-in indexer Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Hardware { STAC6 Series: Model Numbers z STAC6-S z STAC6-Q z STAC6-QE (expanded I/O) z STAC6-Si z STAC6-220-S z STAC6-220-Q z STAC6-220-QE (expanded I/O) z STAC6-220-Si Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Hardware { STAC6 Series: All Models z Microstep Emulation z Torque Ripple Smoothing z Electronic Damping z Encoder feedback option z UL recognized (110 VAC units) Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com

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Visit www.applied-motion.com for more information Sold & Serviced By: Toll Free Phone: 877-378-0240 Toll Free Fax: 877-378-0249 sales@servo2go.com www.servo2go.com