Step and Direction ClearPath servo motors have a servo drive with auto tuning, are whisper quiet, and don’t lose steps

ClearPath-SD

Integrated Servo With Step & Direction Interface

A State-of-the-Art Servo System
that Costs a Fraction of Other Servos

Automatic tuning optimizes the servo for each application
Integrated system—no more motor cable wiring
RAS™ feature provides double-jerk limiting for smooth motion
Step & Direction—widest range of compatible controllers
Digital, opto-isolated inputs for robust noise immunity

PRICES START AT ONLY $257

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All-in-One Systems

ClearPath-SD combines a step & direction vector servo drive, brushless servo motor, and high-resolution encoder into one compact package.

Two ClearPath-SD models are available:

▸ the SDSK model is a servo system for the price of a stepper motor/drive system, but 2-3 times the power;

▸ the SDHP model is more than 4 times the power of the SK model, and although a modest price premium over the SK, compared to other similar power servos, the HP is about 50% lower cost and a compact, all-in-one system.

ClearPath-SD Step and Direction Mode Overview

Easily Upgrade Your Servo System

ClearPath Step and Direction replaces both noisy, low performance steppers and expensive, complicated digital servos

ClearPath-SD

VS. OTHER DIGITAL SERVOS AND STEPPERS

ClearPath-SDHP	Other Digital Servos	ClearPath-SDSK	Stepper Motors

Power

5
ClearPath-SDHP servos offer more power per dollar and more power per cubic inch than any non-integrated servos. State-of-the-art control algorithms harness this power for a great combination of power and finesse.

5
Most brushless servo systems have constant torque out to relatively high speed, which means lots of power.

3
ClearPath-SDSK servo systems have 2-3 times the power of similar sized steppers and cost less.

1
High inductance and high pole count causes torque to drop off rapidly with speed, leading to lower power output.

Accuracy & Repeatability

5
Very good, and ClearPath's proprietary anti-hunt feature eliminates most hunting. Encoder disk runout is minimized by using a precision machined shaft, a zero runout disk mount design, and a fixed rear bearing.

4
Very good, although some servos hunt (dither) if they use high resolution encoders. Also encoder disk runout affects accuracy.

5
Very good, and ClearPath's proprietary anti-hunt feature eliminates most hunting. Encoder disk runout is minimized by using a precision machined shaft, a zero runout disk mount design, and a fixed rear bearing.

3
Generally pretty good, but degraded by a variety of factors: friction, inertia, static forces, temperature, detent torque, etc.

No Lost Steps

5
Servo systems can not lose steps or stall like stepper motor systems.

1
Stepper motor systems can lose position or stall if not designed with a large safety margin.

Smoothness

5
Servos have no resonant zones like steppers, and ClearPath-SDHP will apply as much jerk-limiting (and jerk-derivative limiting) as required to reduce machine vibration and improve settling time.

3
Servos have no resonant zones like steppers. Smoothness of motion depends on the quality of the motion profile and tracking accuracy of the servo.

3
Servos have no resonant zones like steppers, and ClearPath-SDSK will apply a small amount of jerk-limiting (and jerk-derivative limiting) to help smooth out any imperfections in the motion profile output.

1
Steppers need to jump through speeds where they naturally resonate, which causes jerk on start and stop of motion.

Quietness

5
Brushless servo systems are generally much quieter than stepper systems, and ClearPath uses special techniques to further reduce noise: vector AC commutation, skewed stator laminations, exterior rotor magnet design, oversized precision bearings, and others.

5
Brushless servo systems are generally much quieter than stepper systems.

5
Brushless servo systems are generally much quieter than stepper systems, and ClearPath uses special techniques to further reduce noise: vector AC commutation, skewed stator laminations, exterior rotor magnet design, oversized precision bearings, and others.

1
The large detent torque of steppers, and the way they operate, causes them to run noisy.

Load Handling

5
ClearPath automatically optimizes itself for whatever load is connected. Numerous servo control innovations allow ClearPath to easily handle load-to-motor inertia mismatches of more than 100:1.

3
Servos can be tuned to be a wide range of loads, but most servo manufacturers recommend staying within a 10:1 load-to-motor inertia ratio for acceptable performance.

5
ClearPath automatically optimizes itself for whatever load is connected. Numerous servo control innovations allow ClearPath to easily handle load-to-motor inertia mismatches of more than 100:1.

1
Steppers must be mechanically "tuned" to the load friction and inertia in order to work properly. Stepper performance can not be optimized with software.

Vibration

5
Brushless servos systems general have much less vibration than stepper systems, and ClearPath further reduces vibration due to the vector chatter common to many servo systems that use acceleration feedforward and/or aggressive torque loop gains.

4
Brushless servo systems generally have much less vibration than stepper systems.

4
Brushless servos systems general have much less vibration than stepper systems, and ClearPath further reduces vibration due to the vector chatter common to many servo systems that use acceleration feedforward and/or aggressive torque loop gains.

1
For the same reasons that steppers are noisy, they also create a substantial amount of high frequency vibration.

Efficiency

5
Servos are energy efficient because (in theory) they only use current in proportion to the amount of torque needed. ClearPath uses resistance feedforward, back-EMF compensation, and inductance cross-coupling to come very close to theoretical maximum efficiency. This means that very little energy is consumed when the motor is running at constant speed or at rest.

4
Servos are energy efficient because (in theory) they only use current in proportion to the amount of torque needed. Motor resistance, speed and inductance effects degrade theoretical efficiency.

5
Servos are energy efficient because (in theory) they only use current in proportion to the amount of torque needed. ClearPath uses resistance feedforward, back-EMF compensation, and inductance cross-coupling to come very close to theoretical maximum efficiency. This means that very little energy is consumed when the motor is running at constant speed or at rest.

1
Steppers typically run with at least 50% of full current at all times even when running at constant velocity or standing still. This wastes a large amount of energy and causes steppers to run hot even with low loads.

Integrated Motor/Drive/Encoder

5
The ClearPath-SD models priced below combine a brushless, permanent magnet servo motor, encoder, and vector sinewave drive with a step and direction interface, all in one compact package.

2
Expect to pay at least a $200 premium over the prices shown below to get an integrated servo system (other than ClearPath).

5
The ClearPath-SD models priced below combine a brushless, permanent magnet servo motor, encoder, and vector sinewave drive with a step and direction interface, all in one compact package.

1
Expect to pay at least a $150 premium over the prices shown above to get an integrated stepper system (more with an encoder).

Choose a ClearPath-SD Model

Both models share the same state-of-the-art servo performance.
Choose based on power and price.

SDHP Models High peak power, aggressive duty cycles	SDSK Models Lower power, lowest cost position control

Power	Power
▸ 2 times the power per cubic inch of other servos	▸ 2-3 times the power of similar size steppers
Price	Price
▸ 1-Piece: $492 & up ▸ 100/year: $404 & up	▸ 1-Piece: $257 & up ▸ 100/year: $211 & up

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Selection Guide

ClearPath-SD

Integrated Servo With Step & Direction Interface

All-in-One Systems

Easily Upgrade Your Servo System

Choose a ClearPath-SD Model

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