Did You Know... For more information, circle #1 on the reader service card. …that a HEIDENHAIN ERA 4281C angle encoder and a LIP 581 linear encoder are vital components of the High Definition Airborne Gravity Gradiometer from GEDEX Inc. (Ontario, Canada), which, for the first time, can clearly “see” up to eight miles into the earth, identifying mineral (including diamonds) and oil and gas resources. This important gradiometer dramatically increases the certainty of discovery, lowers the cost of exploration and is fast, efficient and environmentally friendly. Called the GEDEX HD-AGG™, it employs gravity to measure minute density variations to identify subsurface geological structures. This next-generation, highly sensitive, breakthrough technology is a quantum improvement over current methods. It is extremely sensitive and provides high definition images of valuable underground deposits that were previously invisible or overlooked. “The high resolution performance of both the linear and angular HEIDENHAIN encoders is key to the gradiometer motion isolation system, as it provides unparalleled accuracy in measuring the system kinematics as well as superior feedback measurements for motor commutation,” said Eric Morrow, a GEDEX Controls System Specialist. GEDEX’s (www.gedex.ca) resource discovery technology is mounted on a patented stability platform isolation system and allows the system to be flown even in moderately turbulent conditions. ■ Fuzzy, confusing missed opportunity Clear, unambiguous diamond discovery Kimberlite Diamond Field: Current Technology GEDEX HD-AGG™ Contents… Cover story continued AMS — 2006 HEIDENHAIN Distributor of the Year Flexible TNC 320 Programming Station Now Available HEIDENHAIN Releases TNC Software Enhancements HEIDENHAIN Opens New Building in Germany New IOBs Increase DRO Capabilities Dear Abbé: “Accuracy of Feed Drives” Page Page Page Page Page Page 2 5 6 7 8 9 Safety-Related Position Measuring Systems HEIDENHAIN offers safety-related position measuring systems that are based on pure serial data transfer via EnDat 2.2 and can be used in safety-related applications. A safety-related position measuring system can be used as a single-encoder system in conjunction with a safe control in applications with control category SIL-2 (in accordance with IEC 61 508) or performance level “d” (in accordance with ISO 13849). The safe transmission of the position is based on two position values generated independently from each other and on error bits. These are then all provided to the safe control. The first encoders available are the ExN 425/437 and ExN 1325/1337 position encoders for servo drives. In the future, this technology will also be used with absolute linear and angle encoders with EnDat 2.2. Safety is becoming increasingly important in machine and plant construction. Proof of this can be seen in new legislation and in the heightened safety regulations of national and international standards. These high requirements mainly serve to protect human beings, but material assets and the environment are also receiving more consideration. The goal of functional safety is to minimize or at least reduce the risks that can occur during normal or impaired operation of machines or facilities. The first step of this is achieved with redundant systems. For example, axes that are moved in safety-oriented applications require redundant position information in order to perform the corresponding safety functions. Various system configurations can be realized in order to capture independent position values. continued on next page Machine Tool Volume 2 • 2007 Equipped with a HEIDENHAIN Safety-Related Position Measuring System
Transcript
Did You Know...
For more information, circle #1on the reader service card.
…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. �
position measuring systems thatare based on pure serial datatransfer via EnDat 2.2 andcan be used in safety-relatedapplications. A safety-related positionmeasuring system can be used asa single-encoder system in conjunctionwith a safe control in applications withcontrol category SIL-2 (in accordancewith IEC 61 508) or performance level“d” (in accordance with ISO 13849).The safe transmission of the positionis based on two position valuesgenerated independently from eachother and on error bits. These are thenall provided to the safe control.
The first encoders available are the ExN425/437 and ExN 1325/1337 position encodersfor servo drives. In the future, this technologywill also be used with absolute linear and angleencoders with EnDat 2.2.
Safety is becoming increasingly importantin machine and plant construction. Proof ofthis can be seen in new legislation andin the heightened safety regulations ofnational and international standards. Thesehigh requirements mainly serve to protecthuman beings, but material assets and theenvironment are also receiving moreconsideration.
The goal of functional safety is to minimize orat least reduce the risks that can occur duringnormal or impaired operation of machines orfacilities. The first step of this is achieved withredundant systems. For example, axes that aremoved in safety-oriented applications requireredundant position information in order toperform the corresponding safety functions.Various system configurations can berealized in order to capture independentposition values.
continued on next page
Machine ToolVolume 2 • 2007
Equipped with a HEIDENHAINSafety-Related Position Measuring System
2
One possibility is using two encoders per axis, but due to cost considerations, a solution with only one position encoder is aspired to in mostcases. Until now, analog encoders with sine and cosine signals were used for this. HEIDENHAIN is now the first manufacturer to offer a purelyserial, single-encoder solution for safety-related position measuring systems in safety-oriented applications according to IEC 61 508. This meansthat safety applications can now take advantage of all the benefits of serial data transfer, such as optimization of costs, diagnostic possibilities,automatic commissioning and rapid formation of the position value.
Basic principle
The HEIDENHAIN measuring systems for safety-related applications are inspected for compliance with ISO 13849-1 (which replaces EN 954-1) andIEC 61 508. These standards describe the assessment of safety-related systems; for example, on the basis of failure probabilities of integratedcomponents and subsystems.
This modular approach helps manufacturers ofsafety-related systems to implement theircomplete systems, because they can begin withpre-qualified subsystems. Safety-related positionencoders with pure serial data transfer via EnDat2.2 accommodate this technique.
In a safe drive, the safety-related position
measuring system presents such a subsystem.The safety-related position measuring systemconsists of:
• Encoder with EnDat 2.2 transmission component
• Data transfer line with EnDat 2.2 communication
and HEIDENHAIN cable
• EnDat 2.2 receiver component with monitoring
function (EnDat master)
In practice, the complete “safe servo drive”
system consists of:
• Safety-related position measuring system
• Safety-oriented control (including EnDat
master with monitoring functions)
• Power stage with motor power cable and drive
• Physical connection between encoder and drive
(e.g., shaft connection/coupling)
Integration of the position measuring system
The position measuring system is integrated via a physical and an electrical interface into the complete system. The physical coupling of theencoder to the drive is determined by the encoder's geometry, and including the EnDat master in the safe control ensures its electrical integration.Certain measures are to be taken for the integration and evaluation of the EnDat master in the control in order to be able to use the safety systemof the position encoder. With regard to a safe complete system, the remaining components of the complete system must also be designed forsafe technology.
Transmission of the position value
Scanning in the encoder simultaneously produces two independent position values that are transmitted using the EnDat 2.2 protocol to the EnDatmaster. The EnDat master assumes various monitoring functions with which errors in the encoder and during transmission can be revealed. Thetwo position values are then compared. The EnDat master then provides the two position values and independent error bits to the safe controlover two processor interfaces. The control monitors the correct operation of the safety-related position measuring system with periodic tests. Thearchitecture of the position measuring system according to IEC 61 508 is regarded as a single-channel tested system.
Safety-Related Position Measuring Systemscontinued from cover
Complete Safe Servo Drive System
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Field of application
Safety-related position measuring systems from HEIDENHAIN are designed so that they can be used as single-encoder systems inapplications with control category SIL-2 (in accordance with IEC 61 508). This corresponds to performance level “d” of ISO 13849 orcategory 3 of EN 954-1. Also, the functions of the safety-related position measuring system can be used for the following safetyfunctions in the complete system (also see IEC 61 800-5-2):
• Safe switch-off
• Safe stop
• Safe controlled stop
• Safe reduced linear or rotational speed
• Safe limited jog increment
• Safe limited absolute position
• Safe limit of torque/power
Requirements to be fulfilled by the
safety-oriented control
Important tasks of the safe control for settingup a safe axis using a safety-related positionmeasuring system are detailed below. Pleasenote that this document does not describeall tasks of the safe control.
• The encoder and the EnDat master mustbe subjected to a switch-on test whenthey are switched on.
• The position values and error bits are to beevaluated by the safe control during operation. Depending on the safety function required, this includes monitoring of the servo lag, standstill monitoring and the comparison of the two position values (Position 1 and Position 2),for example.
• If an error should occur, the control must assume a safe condition. Thereaction that the control triggers when an error is revealed depends on
the application, and is therefore part of the strategy of the drive or
control manufacturer.
• The control is to perform efficiency tests (test interval < 8 h) in the
encoder and in the EnDat master. As part of this, the error bits are
subjected to forced dynamic sampling (i.e., intentionally triggered), and
their reactions are evaluated.
• The following mechanical defects must be detected by the safe control:
– Breakage of shaft or coupling
– Static shaft misalignment
– Dynamic shaft slip
Note: Breakage of shaft or coupling at standstill can be ruled out for certain mechanical designs of HEIDENHAIN encoders.
Requirements for data transfer from the EnDat Master to the further components of the safe control
The EnDat master makes the two processor interfaces 1 and 2 available. Position 1, Position 2 and the error bits must reliably betransmitted to the safe control over these two interfaces. These two interfaces are to be operated by two independent interfaces(two-channel structure) of the control. These could be two different microprocessors, for example. The EnDat master and the encodermust each be supplied with protective low voltage according to EN 60 204-1 with over-current protection (encoder), and over-voltageprotection if necessary, from the subsequent electronics.
Acceptance testing must be defined for when the machine is first put into operation, or when changes are made which influencethe safety functions of the machine.
Safety-Related Position Measuring System
continued on next page
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For more information, circle #2 on the reader service card.
Safety-Related Position Measuring Systemscontinued from page 3
HEIDENHAIN offers encoders for safety-related positionmeasuring systems with purely serial data transfer. Thetwo measured values are already formed independently ofeach other in the encoder and are transmitted to the safecontrol via the universal EnDat interface. This saves youthe cost of expensive connecting cables, eliminatingunnecessary wires.
At this time, two rotary encoders are available in bothsingleturn and multiturn versions as “safe” positionencoders. Further absolute linear and angle encoders arein preparation. �
Presented with the prestigious HEIDENHAIN President’s Award recognizing excellent performance andcommitment to the machine tool industry, Grace Albietz, owner of Accurate Measurement Systems(AMS) in St. Louis, Missouri, recently accepted the 2006 HEIDENHAIN Distributor of the Year Americaneagle trophy. AMS is the only two-time recipient of this award; the first one was granted to them in 1999.
On hand to join Grace were her two sons in the business, Ed and Tim, and Patrick O’Day, the three ofthem representing AMS’ sales, applications, parts and service departments. HEIDENHAIN’s ChrisWeber, National Sales and Product Manager, Machine Tool Division, and Ron Hood, Area SalesManager, made the presentationand announcement based onAMS’ sales, product mix, ease ofdoing business, professionalism andrepresentation of HEIDENHAIN. “Inother words,” said Weber, “thisaward is based on all the facets ofdoing business and the relationshipwith HEIDENHAIN. We are proud tohave them as part of our team.”
AMS specializes in DRO and CNCfeedback equipment and has beenin business almost 30 years. Grace,now widowed, explained that herhusband Ron had started thebusiness in 1980 after serving theearly DRO industry at EmersonElectric and U.S. Motors for manyyears prior. AMS represents theentire HEIDENHAIN product line aswell as handles installation andservice. One of the keys to theirsuccess is their parts management,led by Tim Albietz, AMS’ InsideSales and Parts Manager. “We prideourselves on having the necessarytools on hand to satisfy our customers’ immediate requirements,” explained Tim.
AMS has a long list of clients from not only the Midwest, but from all over the country and even a fewlocated internationally.
“We believe our success is due largely to our team approach and customer-comes-first attitude,” saidEd Albietz, Sales and Applications Manager, “but also involves our substantial experience and expertisein the application of aftermarket DROs and other equipment to a large variety of applications fromstandard to exotic machine tool equipment.
“We believe AMS can be trusted to provide the accuracy needed to handle jobs from a simpleBridgeport mill or lathe in the backyard shop of a lone machinist to an industrial behemoth milling theintricacies of an aircraft carrier gearbox.”
For more information about AMS, visit their website at www.accuratemeasurementsystems.com. �
From AMS left to right: Patrick O'Day, Tim Albietz, Grace Albietz and Ed Albietz 2006 HEIDENHAIN Distributor of the Year
And the Award Goes to AMS for2006 Distributor of the Year
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HEIDENHAIN Releases TNCSoftware Enhancements
Providing advanced capabilities to the already multi-functional iTNC 530 numericcontrol, HEIDENHAIN Corporation announces the availability of the new NC softwarethat contains numerous new functions for machine manufacturers and users.
With over a dozen new functions, the new capabilities promise to bring machiningwith an iTNC 530 to an even higher and simpler level than ever before. Two of thenew highlighted functions include:
AFC – Adaptive Feed Control (option) – This makes it possible to now adapt thecontouring feed rate to the spindle performance, providing various advantagesregarding machining quality, velocity and the permissible usage time of a tool.
GPS – Global Program Settings (option) – This was introduced for tool and moldmaking. It enables the user to enter data in a form, which are superimposed on theprevious data during program run. Various functions are available, from swapping ormirroring axes to entering additional additive datum.
Multiple other functions are possible, too, with this new HEIDENHAIN software suchas additional conversational languages, a TNC guide in the Help system, furtherdevelopment of the smarT.NC remote capabilities, improvement of Dynamic CollisionMonitoring (DCM), and expansion of part programs, to name a few. �
The Versatile iTNC 530 Control
For more information, circle #3 on the reader service card.
For more information, circle #4 on the reader service card.
For those seeking out programming station software for HEIDENHAIN’s TNC 320control, look no further. Now available are three versions.
First, a demo version of the TNC 320 programming software is available that containsall features, though only 50 NC blocks can be saved. This can be downloaded atwww.heidenhain.com.
For interested customers who have already purchased a HEIDENHAIN iTNCprogramming station, they only need now to purchase a USB dongle version of theTNC 320 programming station and simply connect it to the USB port in the panel. Inthis way, both control versions can be operated via the operating panel, though onlyone application can be started at a time.
And lastly, the full TNC 320 programming station is available with an operating panel.This system is operated via the USB keyboard included in the delivery and is enabledvia a USB dongle integrated into it. �
For further information, circle the appropriate number:Article #1 #2 #3 #4 #5 #6 #7
For further information, circle the appropriate number:Article #1 #2 #3 #4 #5 #6 #7
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For more information, circle #5 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
Prompted by positive input from customers using HEIDENHAIN’s highly versatile line of DROs, HEIDENHAIN introducestwo new IOBs (input/output boxes) that promise to continue to expand their superior functionality even more. Thesenew IOBs will not only improve the available functions in both HEIDENHAIN’s ND 780 and POSITIP 880 DROs, but alsoadd new ones.
Specifically, HEIDENHAIN’s new IOB 49 is now available for use with the ND 780 universal DRO, a HEIDENHAIN counterthat is compatible with virtually any manual machine tool, including milling, turning, boring and drilling machines up tothree axes. With the addition of IOB 49, the ND 780 will now provide two additional functions depending uponapplication:
• When the milling application is active, switching functions can be executed (this means that, depending on the position display of one or more axes, relays are activated or deactivated for switching on/off servo drives,for example).
• When the turning application is active, the IOB 49 makes it possible to machine with a constant cutting speed(CSS). Depending on the position display of the X axis, the spindle speed is controlled via an analog interface.For this purpose, the gear stages of the lathe can also be transferred and taken into account.
With use of the new IOB 89, functions are increased for HEIDENHAIN’s POSITIP 880 counter. This counter ischaracterized by its highly conversational guidance capabilities for use on machines with up to six axes. With theaddition of the IOB 89, eight switching inputs and nine switching outputs have been added, thus enabling the sameswitching functions as HEIDENHAIN’s previously established POSITIP 855 DRO.
Both IOBs are mounted via a standard rail (35 mm) in the electrical cabinet of the machine by using the snap-on clip onits housing. The connecting cables have a maximum length of 15 m with the IOB 49 (for the ND 780) and 10 m with theIOB 89 (for the POSITIP 880).
New IOBs IncreaseDRO Capabilities
IOBs (input/output boxes)
For more information, circle #6 on the reader service card.
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Technical Tidbit:
Thermal Expansion IssuesWith changes in temperature, almost all materials tend to growor shrink. This is also true of many HEIDENHAIN linear scales.This can contribute to the overall accuracy specification of yourmeasuring system. All HEIDENHAIN documentation clearlyindicates what this expansion rate is by stating the Expansioncoefficient.
For example, for the LC 183 we specify:
ααtherm approx. 8 x 10-6 K-1
What does this mean? With a 1040 mm scale, for every changeof 1 degree Kelvin, your measuring system will grow or shrink by8 micron (Kelvin and Celsius are on the same scale. A change of1 degree Kelvin = a change of 1 degree Celsius).
It follows, then, that a 20°C temperature increase will result ingrowth of 160 micron or, stated another way: a temperatureincrease of 68°F will result in a growth of approx. 0.006". �
9For more information, circle #7 on the reader service card.
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
HEIDENHAIN CORPORATION 333 E. State Parkway, Schaumburg, IL 601731-800-233-0388 | www.heidenhain.com
At HEIDENHAIN, we believe that learning is like rowing upstream; not to advance is to drop back.
That is why we put so much effort into training and believe wholeheartedly in the concept of lifelong learning. This applies not only to our staff but alsoto our customer base and distribution network.
Our new internal sales structure at HEIDENHAIN is based on markets and products specific to those markets and is in keeping with this concept. In themachine tool division, we concentrate on metal cutting and metal forming applications. Over the last year, our group has been increasing our knowledgeon these markets exponentially to be able to better serve our customers by understanding their machines, applications and product requirements.
At our main office in Schaumburg, Illinois, we have a dedicated training facility designed to offer state-of-the-art training tools, allowing us to proficientlytrain our staff and customers as needed. Each of HEIDENHAIN’s three sales divisions offers distinct product and application training to our respectivedistributors and dealers with courses offered free of charge and held periodically throughout the year.
In this facility, we also hold classes dedicated to TNC programming. Here, end users, machine tool dealers and distributors can attend classes reinforcingour conversational programming on current and previous generation controls. We also offer PLC and commissioning training classes to our Retrofittersand control OEMs to ensure their competency in installing and servicing our control products in the field.
At fixed intervals throughout the year, HEIDENHAIN’s worldwide headquarters in Traunreut, Germany, hold product training seminars and workshops withthe goal of enhancing the skill set and knowledge base of our global technical sales staff. At these meetings, new products are introduced, marketrequirements are discussed and new product development begins. Upon return, each attending representative is charged with imparting the knowledgegained to their respective counterparts in their home country.
Within HEIDENHAIN Corporation, we have a lifelong learning program whereby any employee can take courses, read books, watch videos relevant totheir job and receive credit in the HEIDENHAIN UNIVERSITY program. Each employee at HEIDENHAIN has tuition money set aside for this purpose andthe majority of our employees participate in some fashion.
We see the benefits of our rowing upstream and hope you do, too. �
By Chris Weber National Sales and Product Manager, Machine Tool
