Did You Know...…that a HEIDENHAIN ERA 4281C angleencoder and a LIP 581 linear encoder are vitalcomponents of the High Definition AirborneGravity Gradiometer from GEDEX Inc. (Ontario,Canada), which, for the first time, can clearly“see” up to eight miles into the earth, identifyingmineral (including diamonds) and oil andgas resources. This important gradiometerdramatically increases the certainty of discovery,lowers the cost of exploration and is fast,efficientand environmentally friendly.

Called the GEDEX HD-AGG™, it employsgravity to measure minute density variations toidentify subsurface geological structures. Thisnext-generation, highly sensitive, breakthroughtechnology is a quantum improvement overcurrent methods. It is extremely sensitive andprovides high definition images of valuableunderground deposits that were previouslyinvisible or overlooked.

“The high resolution performance of both thelinear and angular HEIDENHAIN encodersis key to the gradiometer motion isolationsystem, as it provides unparalleled accuracy inmeasuring the system kinematics as well assuperior feedback measurements for motorcommutation,” said Eric Morrow, a GEDEXControls System Specialist.

GEDEX’s (www.gedex.ca) resource discoverytechnology is mounted on a patented stabilityplatform isolation system and allows the systemto be flown even in moderately turbulentconditions. �

Fuzzy, confusingmissed opportunity

Clear, unambiguousdiamond discovery

Kimberlite Diamond Field:Current Technology GEDEX HD-AGG™

Optimized Scanningin Absolute Rotary Encoders

Rotary encoders for electrical drives are subject tohigh requirements: they are expected to functionreliably and provide dependable measurementdata in spite of their often harsh environments.Theoptimized scanning principle—made possible bythe serial-coded absolute track—meets theserequirements. Absolute rotary encoders withoptimized scanning are distinguished by the highquality of their scanning signals and theirsignificantly reduced sensitivity to contamination.An innovative scanning and evaluation unitpermits both high interpolation and optimizedcontrol loop performance. Interpolation andposition value generation within the rotaryencoder permits reliable, purely digital data

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Photoelectric scanning of a Gray-code graduationaccording to the imaging scanning principle

Contents…Cover story continued

Meeting the Need

for Miniaturization

Interactive Semicon Booth

HEIDENHAIN Opens New Building

in Germany

New Benefits with Redesigned

Linear Encoder Program

Visit HEIDENHAIN on the Road

Dear Abbé:“Accuracy of Feed Drives”

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ElectronicsVolume 2 • 2007

For more information, circle #1on the reader service card.

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Optimized Scanningcontinued from cover

transmission and relieves the higher-level electronics. Also, becausetheir safety-related functions comply with IEC 61 508, the rotaryencoders now are ready for use in SIL-2 applications. These changeshave no effect on the dimensions of the encoders; no mechanicalchanges of the motor dimensions are required.

Controlled servo drives are used in many areas of automationtechnology, robotics and handling systems as well as in the drivetechnology of production machines and machine tools. Therequirements regarding dynamics, speed stability and rigidity necessitateever-increasing gain factors in the control loops. The position encodersused have a decisive influence on important motor properties, such as:

• Positioning accuracy

• Speed stability

• Bandwidth, which determines drive command-signal response and

disturbance rejection capability

• Power loss

• Size

The position resolution and the position error within one signal period aredistinctly in the foreground. Decisive factors here are the scanningprinciple as well as the further processing of the scanning signals.

Encoders from HEIDENHAIN generally operate according to the principleof photoelectrically scanning a regularly structured measuring standard.In the imaging scanning procedure, as it is used by absolute rotaryencoders, for example, a structured graduated disk rotates relative to ascanning point. The incident light is converted into electrical signals bythe photovoltaic cells. The absolute position information is determinedfrom the graduation on the graduated disk.

Scanning principle

The scanning principle of rotary encoders with optimized scanninggenerates the absolute position value from just two graduation tracks:the absolute information is encoded in just one track on the newlydeveloped graduated disk. The pattern of this serial code structure isunique over one revolution. The incremental track is located next to it. Itis interpolated for the position value and at the same time is used togenerate an optional incremental signal. The information in the twotracks is processed in the new, highly integrated electronics to forman absolute position value with high resolution (approx. 33 millionmeasuring steps per revolution).

An optical filter is used in the special scanning of the incremental trackto produce very homogenous signals. Instead of the usual individualphotovoltaic cells, one large-area, specially structured photosensorgenerates scanning signals with a good sinusoidal shape and highconsistency, even at very different speeds, for each graduation track.

Higher resolution—better control

The consistently good quality of the sinusoidal scanning signals resultingfrom the optimized scanning significantly reduces the position errors withinone signal period. This is why reliable 14-bit interpolation is now possiblein the rotary encoder. The high resolution achieved by this results in finermeasuring steps,which in turn are definitive for the high control quality andthe finely tuned velocity control.

Consistently accurate

The serial code structure, located in just one track, combined with theoptimized scanning principle, permits a high accuracy of the encoder,independent of the speed. This means that regardless of whether youare operating at the maximum speed or nearly at a standstill, thepositioning accuracy is always consistently high.

Conventional graduated disk with 13 Gray-code tracks

Graduated disk with serial code track and incremental track

Scanning signals shown as Lissajous figures

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Tolerance to contamination

Theoretically, contamination is not an issuewith sealed rotary encoders that areintegrated in electrical motors. In practice,however, traces of oil from bearings, dustfrom the brakes and out-gassing from themotor coil can intrude into the rotary encoder.Due to the large scanning area over the entirewidth of the scale grating and the specialarrangement of several scanning fields,encoders with optimized scanning areextremely insensitive to contamination.

Newly developed scanning and

evaluation electronics

The significant reduction of individualcomponents results in a decided improvementin reliability during manufacture and when inuse. The most important factor here is thereduction of the scanning from 13 tracks to justtwo tracks, as well as the high degree ofinterpolation of the newly developed scanningand evaluation electronics.

These electronics also make it possible toincrease the range for the power supplyvoltage, so that it is now from 3.6 V to 14 V.This means that monitoring of the supplyvoltage in the encoder can be omitted, andso sensor lines and a controllable powersupply in the subsequent electronics are nolonger necessary.

The combination of the new scanning andevaluation electronics with the EnDatinterface offers important advantages.Since interpolation takes place within therotary encoder, purely digital datatransmission, which is less sensitive tonoise, is possible. Since lines for theanalog signals are no longer needed, theconnection cables are less complex,meaning that simpler and thinner cablesare possible, as well as smaller connectingelements. Since the entire position value isalready available to the subsequentelectronics, time-critical interrogations andcalculation operations are avoided.

The EnDat interface makes extensivemonitoring and diagnosis of an encoderpossible without an additional line. The

Position error within one signal period, shown over one revolution

Accuracy relative to shaft speed

Influence of contamination on positioning accuracy (typical measured values)

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diagnostic system generates error messages andwarnings, and is a significant prerequisite for the high levelof availability of the complete system.

For encoders with purely serial interfaces, the valuationnumbers provide the current state of the encoder andascertain the encoder‘s “functional reserves”. The valuationnumbers can be read from the encoder cyclically via theEnDat 22 interface without influencing the quality of theaxis control.

Rotary encoders for safety-oriented applications

For future-oriented applications, the question of safetystandards is becoming increasingly important. That is whythe functional safety as per IEC 61 508 was already takeninto account when designing the new scanning andevaluation electronics. Scanning in the encodersimultaneously produces two independent position valuesthat are transmitted using the EnDat 2.2 protocol to theEnDat master in the subsequent electronics. The EnDatmaster assumes various monitoring tasks, and providesboth position values via two independent processorinterfaces to the safe control. Safety-related positionmeasuring systems from HEIDENHAIN are permitted assingle-encoder systems in applications with controlcategory SIL-2 (in accordance with IEC 61 508) orperformance level “d” (ISO 13849).

PCB for absolute rotary encoders with optimized scanning (via opto-ASIC), and PCB with scanning via four photovoltaic cells

Screen showing the valuation numbers as functional reserves (e.g., with IK 215)

Optimized Scanningcontinued from page 3

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Safety-related position measuring system, consisting of an encoder, the datatransmission line and the EnDat master

Available rotary encoders with optimized scanning

HEIDENHAIN is gradually converting its absolute rotaryencoders to optimized scanning. The following variantsare available:

• ECN 1325/EQN 1337

• ECN 425/EQN 437

• ROC 425/ROQ 437

Two rotary encoder models are already available for safety-related applications:

• ECN 1325 singleturn version

• ECN 1337 multiturn version

More absolute rotary, angular and linear encoderswill follow. �

For more information, circle #2 on the reader service card.

For more information, circle #3 on the reader service card.

News:

An Interactive HEIDENHAIN Booth at SEMICON

With demonstrations and opportunities to manipulate product, HEIDENHAIN will showcase its wares at the annual SEMICON West 2007 Showin San Francisco, California (July 17-19). SEMICON is a leading trade show for those interested in semiconductor design and manufacturing.

Multiple opportunities for product interaction will be available at the booth, including giving visitors the opportunity to mount an encoder (ERA4000) by themselves, quickly and efficiently. Other opportunities include manipulating a working high accuracy exposed linear scale (LIP 200)which is an enabling technology encoder with specifications not seen before by the motion industry. “Visitors will certainly have some first-timeopportunities at the HEIDENHAIN booth this year,” said Kevin Kaufenberg, HEIDENHAIN’s National Sales and Product Manager, Electronics.

In general, HEIDENHAIN’s 50’ x 30’ booth will host a variety of available products, from exposed linear scales to a variety of other types ofencoders. Technical staff will be on hand to answer questions and discuss trends and thoughts for the future.

Private showings in a separate meeting room of some new high-end products will be available by appointment only. For more information, contactkkaufenberg@heidenhain.com.

Stop by HEIDENHAIN booth #6170 to learn about the latest!

Meeting the Need for Miniaturization with a New High Accuracy Linear Scale

An increasing number of applications require ever-smallercomponents, especially in the semiconductor and electronicsindustries. HEIDENHAIN Corporation, long setting the standardsfor accuracy and reliability in measurement components(especially evident in the LIDA 400 exposed linear scale), isnow offering even smaller linear scales with the LIDA 500series in order to meet this need for constant miniaturizationand reduction of mass.

These new 20 µm incremental linear scales are useful whereinstallation space is limited, and offer measuring steps of 1 µm to0.1 µm. Their reduced mass gives them higher dynamic capability.

The LIDA 500 scale series - LIDA 583 and LIDA 573 - each havetwo smaller scanning fields with double-field scanning. In order

to compensate for the known disadvantages of small scanningfields, the signal is corrected online electronically, thusproducing better signals.

The LIDA 500 series features glass scales as the measuringstandard, and each encoder has a reference mark at themidpoint. They feature a ± 5 µm accuracy grade and a highdegree of immunity to contamination. Easy mounting ischaracteristic of HEIDENHAIN’s LIDA encoders, and this is noexception.

The series offers 1 Vpp or TTL interfaces. �

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IS INTERESTED IN YOUR FEEDBACK

©2007 HEIDENHAIN CORPORATION

333 E. State Parkway, Schaumburg, IL 60173Phone: 847-490-1191 FAX: 847-490-3931

333 E. State Parkway, Schaumburg, IL 60173Phone: 847-490-1191 FAX: 847-490-3931

Please send me HEIDENHAIN’s most current catalog:

� General � NC Linear � Digital Readout � METRO/CERTO Gauges

� Measurement Inspection � Angular Rotary � Incremental Rotary � Absolute Rotary

� Contouring Controls � Point-to-Point Controls � Servo Drive

Your comments about topics addressed in this issue and topics you’d like to see in future issues:

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E-mail

� Please add me to your mailing list. (Provide address above.)

IS INTERESTED IN YOUR FEEDBACK

Your comments about topics addressed in this issue and topics you’d like to see in future issues:

Name CompanyTitleAddressCity State ZipPhone ( ) FAX ( )

E-mail

� Please add me to your mailing list. (Provide address above.)

©2007 HEIDENHAIN CORPORATION

Please send me HEIDENHAIN’s most current catalog:

� General � NC Linear � Digital Readout � METRO/CERTO Gauges

� Measurement Inspection � Angular Rotary � Incremental Rotary � Absolute Rotary

� Contouring Controls � Point-to-Point Controls � Servo Drive

ELECTRONICS VOLUME 2

ELECTRONICS VOLUME 2

For further information, circle the appropriate number:Article #1 #2 #3 #4 #5 #6

For further information, circle the appropriate number:Article #1 #2 #3 #4 #5 #6

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For more information, circle #4 on the reader service card.

As 2006 closed as a record-breaking year for unit sales ofHEIDENHAIN encoders, the company began the new year supportedby the opening of a recently completed building at its worldheadquarters in Traunreut, Germany. This new, approximately 135,000square foot facility is now in use for the purpose of encoder assemblyand R&D, and is the largest single investment in the history of DR.JOHANNES HEIDENHAIN GmbH.

The construction of HEIDENHAIN‘s new building began in July 2004.Prior to that, many of the encoder assembly operations in Traunreuthad reached the limits of their capacity. The production volumes ofseveral product groups had doubled in the years prior, and some hadeven tripled. The automatic assembly systems for rotary encoderswere running in three shifts, often in six-day weeks.

The new building, designated A30, has five floors, each withapproximately 27,000 square feet and currently holds about 600employees. The basement is divided into three approximatelyequal areas: the assembly area for high-accuracy encoders,primarily for OEMs in the electronics industry; the long-termtesting for product qualification during the development process;and the technical facilities. The ground floor and 2nd floor (seefigure) house the assembly area for linear encoders, rotaryencoders and angle encoders. Large parts of the 1st floor areused for air recirculation of the production level below it; theremaining spaces provide break rooms for the production

employees and offices for production planning and productionengineering. The 3rd and 4th floors of the new building offer spacefor the offices and labs of the R&D for encoder mechanics, R&D forencoder electronics, and encoder quality assurance.

The complete process of encoder assembly and packing takes placeon the same floor.This makes it possible to improve both productivityand logistics and eliminates unproductive transports and storage thatrequire additional accounting work. In several areas, the door-to-doortimes can be reduced.A larger column interval and large ceiling heightenhance the existing areas for more flexible use, enabling engineers toreact more quickly to changes in the product program and more easilyadapt their manufacturing processes. It becomes much simpler toplan, set up and operate assembly systems. The controlled roomclimate improves process stability and quality, particularly in adhesiveand joining processes. �

HEIDENHAIN Opens New Building in Germany to Accommodate Growth

HEIDENHAIN Corporation announces updates and enhancements to itswell-known, high-quality linear encoder program. The mechanics andelectronics of HEIDENHAIN’s LC Series absolute linear encoders havebeen fundamentally redesigned from the ground up to better meettoday’s measurement requirements, and now include three interfaces --HEIDENHAIN’s EnDat 2.2, FANUC 02 and Mitsubishi.

Specifically, HEIDENHAIN’s new encoder models are the LC 183 M and483 M series with EnDat, FANUC or Mitsubishi. These encoders offermore electrical advantages than ever before, including making purelyserial axis-control possible. The resolution of the absolute position valueis 5 nm for encoders with an accuracy grade of ±3 µm and 10 nm forencoders with an accuracy grade ±5 µm with the EnDat versions. Also,regardless of the measuring length, the data word length is 32 bits andwith a clock frequency of 8 MHz, the formation of the position value andtransfer takes approximately 20 µs. Both output formats also incorporatethe single-field scanning technique ensuring optimum signal quality, hightraversing speed and contamination resistance. Maximum cable runs alsohave increased with the new interfaces.

The lower-cost EnDat connection technology and common cableassemblies (LC 1XX / 4XX) further reduce costs and decrease inventoryrequirements. Encoder diagnostics take place via additional informationin the serial protocol.

Along with the new interfaces, changes to mounting methods have beenmade with these HEIDENHAIN absolute linear encoders in order tosimplify their installation in a wide variety of applications. Encoders of the400 series can now utilize a universal mounting spar when required,which allows for a cable outlet to the left or right. Available accessoriesalso include clamps as an alternative that are mounted at fixed intervalsalong the measuring length to provide additional support.

Encoders of the 100 series have a left and right cable outlet directly onthe scanning unit. The unused socket connector is protected by a cap. �

LC Linear Encoder

Technical Tidbit:

What Is an IP Rating?An IP rating number is often used when specifying the environmentalprotection afforded by enclosures around electronic equipment.

The first number in this rating refers to the protection against solidobjects and the second number against liquids. So, what does a BOXwith an IP65 rating mean?

It means this BOX provides a level of protection that has total protectionagainst dust (no ingress) and it can be immersed in water (to a depth of15cm—1m at this rating).

Note: All HEIDENHAIN product catalogs specify the IP rating for anygiven product.

New Benefits with RedesignedLinear Encoder Program

For more information, circle #5 on the reader service card.

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9For more information, circle #6 on the reader service card.

Visit HEIDENHAIN on the Road

HEIDENHAIN will exhibit at these remaining 2007 trade shows.Please stop by! �

SEMICONJuly 17–19Moscone Center—NorthSan Francisco, California

National Manufacturing WeekSeptember 25–27Donald E. Stephens Convention CenterRosemont, Illinois

Quality ExpoSeptember 25–27Donald E. Stephens Convention CenterRosemont, Illinois

Dear Abbé…This column promises to answer questions related to accuracy issuesin measurement. HEIDENHAIN welcomes your questions.

Dear Abbé,

I read your technical paper,“Accuracy of Feed Drives” which discusseslinear vs. rotary scales during machining, thermal issues and positionerrors. How do I check the accuracy of my machine?Sincerely,Diligent

HEIDENHAIN‘s “Accuracy of Feed Drives” white paper is available at:heidenhain.us/accuracy

Dear Diligent,

HEIDENHAIN offers a number of devices specifically designed tocheck various aspects of your machine‘s accuracy and geometry.

An important one is HEIDENHAIN‘s VM 182 comparator system,which incorporates a steel scale with a graduation of very highaccuracy and a scanning head that moves over the graduationwithout mechanical contact. This device provides a comparativemeasurement versus the motor encoder/ballscrew at accuracy of± 1 µm. In addition to determining the position error, the VM 182also measures guideway error orthogonal to the traverse directionof the machine axis. The resulting error values can then be usedfor acceptance testing and will also provide clear benefits of linearencoders for machine tool positioning.

The VM 182 achieves this by its design. During mounting, thescanning head is connected to the scale by an auxiliary carriage. Thescale is clamped paraxially onto the machine table, and the scanninghead is connected to the machine quill with a coupling magnet. Therelatively large tolerances of the VM 182 facilitate mounting andadjustment. After mounting is completed, the auxiliary carriage isremoved from the scanning head.

Other HEIDENHAIN tools for machine tool inspection and acceptancetesting include the KGM Grid Encoders and Double Ball Bar. �

The VM 182comparator systemon the table of amilling machine

Motion error tracefrom a comparativemeasurement withthe VM182 fordetermining staticpositioning accuracyand guideway error(ISO 230-2)

You may have noticed HEIDENHAIN’s most recent addition to the LIDA family of encoders with the LIDA 500 system. Unfortunately, most people seeencoding technology as just another line item to order for the machine they are building. They don’t realize its complexities until they get to this lineitem. With our breadth of line of encoder technologies, we would like to help the users of encoding technology understand the LIDA family andwhat it has to offer.

First, the LIDA series of encoders consists of high quality exposed scales using the imaging principle. This means that an image of a series of linesis generated by an LED and a reticle inside the scanning unit, projected onto the scale graduation, then reflected back into the scanning unit forconversion to Sine and Cosine electrical outputs. This imaging principle works like a Vernier caliper and uses a large image window to average overmany lines, so that the principle is highly resistant to contaminations on the scale.

The scales themselves are now offered in different materials to consider thermal growth aspects of the machine.The main versions are usually steeltape with the graduation exposed onto the tape substrate. These steel tapes are usually then placed into an aluminum extrusion, so that if the tapeis damaged in some way, the tape is easily removed and replaced in the same exact position. The extrusions also help to bridge gaps that themachine may have, where these gaps would give grief to the “stick on scales.”

Other substrates available for the LIDA series are normal glass, Zerodur ceramic and Robax glass. These substrates improve accuracy and helpdefine the thermal characteristics of the machine.

With gratings that span from 20 µm to 200 µm, a full range of applications are met. From advanced semiconductor machinery to high-speed medicalequipment to quick-and-dirty mounting on less precise axes, the LIDA 100, 200, 400, and 500 systems cover the bulk of midrange to less accurateapplications.

With various scanning unit sizes, three different ways to mount the stainless steel tape graduation, integrated limit switches, bi-directional referencemarks at the same resolution as the incremental track, multitudes of resolutions from 200 µm down to 50 nanometers, and short wave accuraciesto 200 nanometers, you’ll be sure to find the right LIDA encoder for your application.

And HEIDENHAIN is not yet done with the development side of this line. With more flexibility of cable routing, scanning heads able to readdifferent graduations and improved scratch-resistant graduations, there is much more to come with this series! Stay tuned. �

By Kevin KaufenbergNational Sales and Product Manager, Electronics

LIDA Encoding TechnologyNot Just Another Line Item

HEIDENHAIN CORPORATION 333 E. State Parkway, Schaumburg, IL 601731-800-233-0388 | www.heidenhain.com