Excerpts presented here are taken from a transcript based on written responses from the panel members after the original roundtable, scheduled for September 12, 2001 during the ISA conference in Houston, Texas, was cancelled due to the previous day's attack on America. Produced by Industrial Controls Consulting Div., Bull's Eye Marketing, Inc; Published November 2001.

Moderator: Thomas B. Bullock

Participants:

• Groum Gedle, National Sales Manager, Automation Intelligence, A Sanyo Denki Company


• Pat Dvorak, National Sales Manager, Bosch Rexroth Indramat


• John Walewander, Marketing Manager, Parker Hannifin Corporation Compumotor Division


• Curtis Wilson, V.P. Engineering & Research, Delta Tau Data Systems, Inc.


• Edward L. Steiner, President/Sales Manager, Industrial Indexing Systems Inc


• Brian Casey, Global Marketing Director, Rockwell Automation Industrial Motion Control


• Michael Backman, Director of Marketing, Anorad Corporation, A Rockwell Automation Business


• Jayson Wilkinson, Motion Control Product Manager, National Instruments


• Joseph B. Martin, VP- Sales & Marketing, Giddings & Lewis Controls, Measurement, and Sensing


• Christopher Fournier, Western Regional Manager/ Semiconductor Marketing Specialist, Control Technology Corporation

Thomas Bullock: This is the seventh annual Motion Control Forum. It is sponsored by the Industrial Controls Consulting Division of Bull's Eye Marketing Incorporated, which is mainly a market research company, and by ISA-the Instrumentation, Systems, and Automation Society.

* * *

Is open architecture affecting the products you are offering?

Brian Casey: Yes, the words "open architecture" can mean different things to different people. Some of the expectations might be:
1) PC based control systems -- expectation that software and hardware components can be integrated together and run on a variety of vendor independent platforms, with a common OS -- typically Windows NT, CE Linux or other.
2) "Open networks" -- motion bus, fieldbus, enterprise networking -- expectation that devices from multiple vendors can exist on the same network and deliver similar performance and functionality. Examples of open network solutions include SERCOS, ControlNet, ProfiBus, and Ethernet (just emerging at the fieldbus level.)
3) Programming standards -- i.e. IEC 1131-3 -- expectation that application programs can be moved between controls from multiple vendors without application rework while exhibiting the same behavior.
4) Integration of Web technology -- i.e. Web browser access to data, including field devices (status and configuration), diagnostics, and production information.

The impact on Rockwell products is clear.
1) We offer IEC1131-3 based control architecture and language support.
2) We provide open network capability including EtherNet IP, DeviceNet, ControlNet, and SERCOS.
3) We have a common architecture supported across a multitude of platforms including a full soft implementation for Windows NT, 2000, and CE.
4) We offer integrated Web browser technology.

Edward Steiner: Open architecture is affecting everyone's product offerings. We see customers demanding open systems with well-documented standards such as DeviceNet, Sercos, ProfiBus and of course the PC.

Michael Backman: We have always seen a strong desire from customers for standard hardware architecture (VME in the old days, then ISA, and now PCI) and programming interface/tools support (whether NT, VB, ANSI-C, etc) for all the obvious reasons -- compatibility with non-motion based products (e.g. vision boards, I/O), second sourcing, etc. However, in markets that push the performance and functionality envelope (such as semi and electronics), real world limitations of other puzzle pieces can easily reduce the importance of "openness."

Jayson Wilkinson: One of our core strengths is that we have open architecture products. I realize that there seem to be many different definitions of open architecture today. For our products, we define open architecture as the ability to create and modify motion programs on our motion controllers without being forced to use non-standard development environments. LabVIEW, one of our core products at National Instruments, is one of the most common programming languages used in the test and measurement field. LabVIEW works with many different products, including many competitor products.

Christopher Fournier: The desire for interoperability and enterprise connectivity are driving more and more suppliers toward open architecture designs. At CTC we already offer several open standard communication links with our products including: DeviceNet; Ethernet TCP/IP; and Modbus. The conclusion of OMAC and several other groups is that there is an overwhelming desire among both Industrial Automation and Information Technology professionals to standardize on Ethernet wherever possible and that is what CTC is doing.

Groum Gedle: The answer to this question is absolutely YES. AI is one of the very few motion control companies that early on adopted the open architecture platform. AML is 100% software. It runs on a PC with Windows NT operating system or on our imbedded controller that runs on VxWorks. Since its inception about eight years ago, AML has been able to run on 286, 386, 486, PI, and PIV machines. As the power of PCs grows, so does AML.

John Walewander: Compumotor is a proponent of open architecture controls and believes it will increase the robustness and quality of motion systems since it decreases the amount of variability in components. Compumotor has been an ongoing participant in the OMAC sponsored user group for motion in packaging and has found the meetings informative.

Pat Dvorak: Indramat has embraced Open Architecture since the late 80s when our MTCNC was introduced with a front end that ran on Windows. Since then, both Indramat and Bosch have produced motion control hardware and software for the PC platform including standard fieldbuses for both General Purpose and CNC applications. This has paid off as PCs, and Windows in particular, have become an expectation by the factory automation users, rather than something you would need to convince them of.

What impact do you think OMAC (Open Modular Architecture Control) is having on the control and motion markets?

Edward Steiner: Frankly we have not seen any demand for OMAC coming from our marketplace. OMAC is an attempt at some sort of standard but it does seem to have enough exposure or commitment from a large organization to make it a viable standard.

Curt Wilson: Committee based approaches such as OMAC will have important but limited impact. Too many people remember earlier efforts by the automotive companies to force their suppliers into complex standards; these failed miserably, along with companies that made the mistake of believing the automotive companies.

Jayson Wilkinson: OMAC does not seem to be having a very large impact on the motion control market yet. One of the difficulties is that in doing things such as defining a standard HMI, we limit the flexibility and risk missing something. Because we have always been open architecture, OMAC has not really affected us. Our current plan is to continue to offer open architecture controllers and take advantages of standards that come for the motion control industry.

Joseph Martin: One of the biggest benefits of OMAC is the transformation of the market from a "brand standard" to a "technology standard" point of view. As the OMAC standards emerge, customers are recognizing that there are certain standards (i.e. IEC 1131 for programming and SERCOS for motion networking), which will benefit all of their applications. Being a full functional supplier and not one of the biggest name suppliers, OMAC is helping G & L. We are now selling capability and not what name is on the label.

Groum Gedle: As to the question of OMAC having future impact on the motion and control market, I welcome the effort. AI will continue to take part in OMAC meetings to better understand and also influence, where possible, the adoption of open architecture for motion. To date, our SMS controller is one of the few SERCOS controllers I know of that has been tested in the field to have worked with other vendors' drives. The progress that has been made with SERCOS NA and throughout the SERCOS community to address the issue of interoperability is what I believe will be of interest for OMAC. Talking informally to some of the executive members of OMAC has given me the impression that SERCOS as a motion bus standard is getting more prominence now than before because it is addressing the arduous task of interoperability (multivendor product standard). Proprietary controls are a thing of the past, and members of the OMAC community do not want to be confined to using a one vendor solution in the future. Connectivity and standardization are increasingly forcing competitors to work together to tackle these important issues.

Pat Dvorak: Indramat and Bosch AST have participated in OMAC since its inception and it has helped solidify our commitment to produce "Open" products. One of the most significant benefits of OMAC is that it provides a forum for end users to express their expectations, benefits and even difficulties with Open Architecture and Interoperability between Motion/Machine Control and the rest of the factory.

Brian Casey: The key to the OMAC packaging working group activity is to bring End Users/OEMs/Vendors together so that Vendors can develop solutions that deliver the performance and features that End Users and OEMs need. The OMAC packaging-working group is not a standards organization; instead, it helps promote development and adoption of open technology suitable for the packaging industry. For example, OMAC has been lobbying SERCOS to enhance device conformance testing to insure complete interoperability of device from different vendors. Although the impact of the OMAC packaging-working group has been limited to date, the long term potential exists for it to have broad influence because there are a number of high profile vendors, end users, and OEMS that are participating and support the OMAC packaging-working group.

What future do you see for Linux as an operating system?

Jayson Wilkinson: The future of Linux seems very uncertain to me. One of the problems I see with Linux right now is that Windows has so much momentum in both the consumer and engineering markets that Linux will have a difficult time penetrating those markets unless it shows some real important benefits. Right now, Linux seems to have some benefits over Windows in terms of stability and lower costs but I feel that people do not value those benefits enough right now to go through the difficulty of making the switch. In general, people who are content with Windows are not interested in a drastic change. National Instruments supports many products on Linux but we have not seen a high enough demand to justify supporting all of our products on Linux.

Brian Casey: Although there is not a lot of Linux based industrial control solutions, there are some recent introductions. Because of the open source code nature of Linux, it has the potential to grow into an OS that is highly optimized for industrial applications.

Edward Steiner: There are a few people working with Linux, but we see more Windows CE and Windows NT in an attempt to do real-time control.

* * *

Embedded Web servers have been introduced to the market. What will their impact be?

Christopher Fournier: CTC developed the first Web server technology for industrial controllers in the 90s. We are very excited about this segment of the market and we are expanding our offerings in this area. Through the use of embedded server technology much of the current middleware can be eliminated. No longer do you need to have a PC running complex software for motion monitoring or control.

Groum Gedle: Embedded Web servers are great tools for OEMs and their product suppliers. Downtime in any manufacturing process equates to loss of production and thus revenue. Many companies cannot afford to wait for service technicians and technical support people to come to their facilities to troubleshoot problems on their machines. Having the capability to dial in and have access to the machine remotely cuts the machine downtime and eliminates expensive travel to the location of the machine.

John Walewander: Web servers have been introduced for several years now and so far have had little impact in the industry. One reason might be that customers are currently able to do most of what a Web server can provide by sending pertinent machine control information to a PC where a Web server typically resides. Compumotor, for example, can provide all key data from its 6K-motion controller to a PC via its Ethernet Fast Status port. The advantage here is that a customer can incorporate this data and utilize and display it using the front-end software package of their choice. So we believe that the key requirement is the ability to communicate key application data to an open PC for enterprise use.

Brian Casey: Like so many of the Internet technologies, Web servers provide both a new model of doing things as well as working technology to aid implementation. Web servers can be useful for data consolidation, transfer, and visualization. They will evidence themselves in motion systems in both a native or standard format and in customized versions where only some of the technology is employed to deliver a certain function.

Edward Steiner: Embedded Web servers are a flashy technology that has not reached practical application yet. Using Ethernet or the phone line, many companies are running diagnostics, data acquisition or doing recipe downloads. What does the embedded Web server bring to the market? Do users really want their equipment "on the Web" and subject to all the pirates out there? Not yet, maybe never!

Curt Wilson: More and more machines will be Web enabled. Presently, machines that are Web enabled handle this through a PC, but the embedded servers will allow simpler machines to do this. Initially, this will mainly be for remote monitoring and diagnosis, but many other uses will develop.

Jayson Wilkinson: Embedded Web servers have a lot of potential for things like publishing diagnostics and remote monitoring, but do not seem to have as much potential for control yet. One of the big concerns many engineers have about using the Internet for control is that it might open up the possibility for people to get through security and take control of the machines. However, Web servers that can publish data and diagnostics about the machines can be very useful for monitoring data from remote locations.

Joseph Martin: Taking advantage of the ability of motion control systems to serve up data to the Internet is still in its early days. The ability to provide a consistent, widely accessible view of systems will be very beneficial, both from a supplier and customer point of view. Direct visibility of system parameters will ultimately result in improved machine uptime.

Personal computers (PCs) are finding their way into control and motion systems. How is the PC market affecting the controls market?

John Walewander: The PC is giving users and OEMs more flexibility in designing systems. A user can implement a PC for many reasons now from soft logic to MMI to motion or any combination. If anything, the PC is making the task of choosing the best control and motion solution more difficult than ever. With its sister company, Parker CTC, Parker Automation is defining a new type of Machine Control system; the PCLC or PC-based logic control system. This solution provides the open environment inherent with PCs without having to reeducate the entire factory. Because the system offers all the IEC-61131 PLC programming languages, there is no need for incremental learning.

Key advantages with this control scheme also include:

• Real-time and deterministic behavior, just like a PLC.


• Maintainable just like a PLC.


• Reliable hardware and software integration when using HMI.


• Standard network support for ease of information flow and common development environments save time and money.


• New engineers are more familiar with PCs than with PLCs; open architecture means more options for the customer.


• Fully integrated system solution available through one vendor -- motion, HMI, and PLC all fully integrated.

This type of control platform will have advantages for motion systems since it will allow increased and higher level communication between the motion control and the machine control.

Pat Dvorak: The use of PCs is part of virtually every motion control system today. This can span the range from Programming Tools, HMIs to PC Hardware Based Controls to "Soft" Controls. As a global society grows up using PCs for day-to-day activities, many current and future manufacturing staff are and will become more and more comfortable with the platform. Leveraging the Office Automation Market affords economies of scale that far surpass anything we could ever realize in only factory automation, thus the PC will help drive controls costs in a downward direction while enhancing performance.

The remaining issues will be enhancing robustness, product life cycles, and meeting unique performance needs.

Brian Casey: There has been a significant amount of hype regarding growth of PC-based Control Systems, and the eventual replacement of the PLC. To date, however, we have not seen significant adoption of PC-based control as predicted. For the most part, the PC controls systems have been limited to high end, data intensive applications. There are still questions about reliability (i.e. suitability of disk drives on the plant floor), suitability of NT/ Windows 2000/CE OS for real time, industrial applications, and cost effectiveness (white box computers are not suitable for most industrial environments and industrial computers are very expensive).

However, I do expect to see adoption of PC-based controls technology increase in the future. Some key elements of this adoption will include availability of smaller, lower cost, embedded computing platforms (i.e. CE-based OI devices running motion and sequential control), better integration of control disciplines like motion and sequential control, and improvements in the real time capabilities and robustness of commercial operating systems.

Rockwell offers a full soft solution supporting Windows NT, 2000. Windows CE support is currently under development. The key to the Rockwell approach is that this is one of a multiple of platform options which all share common programming, functionality, lookand feel. In fact, it is possible to move an application between multiple platforms with little or no application rework.

Edward Steiner: PCs are finding their way onto the factory floor, but we are still not convinced a user should trust real time control to a PC. The strength of a PC is to run third party applications that interface to a machine. These third party software applications are typically HMI, data acquisition and analysis, networking, or diagnostics. These third party applications are not designed to be real time applications and could bog down a PC trying to do real time control.

IIS has taken a different approach in our EMERALD product line. The EMERALD controller is a dedicated real time controller to run the machine while letting an embedded PC run third party applications. This is a somewhat different strategy from most companies using PCs for control.

Curt Wilson: PCs are increasingly being used as the front end in motion control systems, handling the user, storage, and network (including Internet) interfaces. There is a lesser, but also increasing, use of PCs for the actual control, presently more for logic and process control, but now starting for motion control as well. Key concerns are the stability of the hardware and software platforms, and the ease of writing the code. Companies that do just some of the real time motion calculations in the PC generally won't touch any application of less than 100 units per year; otherwise they cannot justify the investment in the difficult programming. Similarly, companies that do all of the motion calculations in the PC generally won't touch an application of less than 500 units per year.

Jayson Wilkinson: Some of the important ways PCs are affecting the controls market are:

• Lowering overall system costs: Motion controllers that can be plugged into the PC help to lower the overall system cost because they are often based on off-the-shelf components and help to reduce development time with easy-to-use software. Upgrading them can often be as simple as taking the old controller board out and installing a newer version in its place.


• Making motion control programming easier: Using standard programming languages available on the PC such as C/C++, Visual Basic, or LabVIEW, makes developing motion system software easier because the developers do not have to learn special proprietary languages and can implement other parts.


• Making motion easier to integrate with other systems: By using the PC as a control platform, motion system designers can easily add in other features such as data acquisition and vision to their systems. Using standard application development environments, they can program the motion, vision, and data acquisition in the same programs and have a central location for all of their system control and monitoring tasks.


• Making motion systems more flexible: With all of the software and hardware available for controlling, monitoring, and analysis, the PC is a very flexible platform. Motion systems based on the PC platform can take advantage of this flexibility. Modifications to systems based on the PC are much easier to modify to meet both present and future needs.

Joseph Martin: Personal computers are just another vehicle to deliver control functionality. Most customers see their use as a way of lowering hardware costs, but not necessarily increasing the control performance. To differentiate themselves, suppliers of PC-based motion controls must sell more on functionality of the motion controller and not so much on the physical size or robustness of the package. A caveat to the PC market is if the motion control must be in a harsh environment. A PC-based motion controller may not be the best fit for every application.

Christopher Fournier: The computing power of today's PCs is sufficient for most control applications. So from a cost per computing operation, the PC is a great value. However engineers need to keep in mind that PCs are designed and optimized for use in home/office applications. After all, this is where they are getting unit volume in the millions. When considering the use of a PC in an industrial application, especially where real time control is required, engineers should proceed with caution. Make sure you take the following into consideration:

• How will I guarantee real-time performance?


• Is the hardware suitable for the environmental conditions that will be encountered?


• What type of software is required?


• Who will write and maintain the custom software?


• Who will handle compatibility issues that arise from integrating your own software solution -- both initially and as 3rd party vendors change their hardware and/or software?


• Who will do the documentation?


• What type of support is available?

Groum Gedle: It is apparent that the use of PCs in motion control has grown dramatically from the 80s to the 90s and onward. PLCs still dominate the motion industry. However, PCs are becoming more and more accepted in the motion control industry because of their flexibility and quick adaptability. PCs are also more affordable now than they used to be 10 years ago. Another reason why PCs are becoming more accepted in the motion industry is because motion control companies have introduced PC-based motion controllers that are open, flexible, and scalable. The end user can run multiple programs from the same PC that not only includes motion but other functions as well.

Will faster and more powerful CPUs result in drives becoming smarter or dumber (simply power stages)?

Groum Gedle: We are seeing more and more drives being digitized with a built-in CPU or DSP to allow them to do things that were traditionally done by the controller. This allows the servo system to be more responsive. Automation Intelligence digital drives close the current and velocity loops in the drive. Our controller simply sends position commands that are micro-interpolated in the drive as well. As a result, our controller does not require high bandwidth, as is the case if we were to close all the loops (current, velocity, and position) from the controller.

John Walewander: Both scenarios are currently active and will continue. There are times when it makes sense to decentralize your motion control system and use very powerful DSPs in smart amplifiers. On many DeviceNet and Profibus networks this is the case. However, for the truly low cost you need a powerful centralized motion controller connected to inexpensive digital drives with inexpensive DSPs and a motion bus.

Faster and more powerful CPUs will benefit both servo controllers and drives primarily by improving the cost/feature ratio.

From the controller standpoint, the additional CPU horsepower will be used for supporting a wide variety of communication options both at the enterprise and drive level. Additionally, it will become more economical for direct interfaces to higher end encoder options like Endat, SinCos, and Hyperface.

From the drive standpoint, increased CPU horsepower will allow better current regulation and more sophisticated motor and drive protection. In addition, true sensor-less control for commutation will become available for the masses with the use of the latest low cost DSPs.

In the future, there will be a continual need for "dumb" amplifiers that require the ubiquitous +/-10V torque command. Today this is addressed with a mixture of analog and digital designs depending on the power level, feedback option support, and required features. The trend will continually shift toward the 99% digital design at the point where the costs are equal or better. As drive costs continue to decline, the analog to digital converters are becoming a high cost item. A low cost digital motion interface needs to emerge which will satisfy the high data speeds and also have a very low incremental cost to the drive and controller.

Pat Dvorak: At Bosch Rexroth, we have always come to market leading with "Intelligent" drive technology. Many of the complex high axis count applications we have encountered would simply not have been possible without intelligent drives. Our current drives development is leveraging higher processing power to add real world user benefits such as faster loop closure rates, high speed motion macros and imbedded logic control capability with "IST." IST stands for "Integrated Safety Technology" and is a major initiative in Europe to incorporate features into smart drives so their reaction in various machine conditions will ensure safety though internal control algorithms. This would not be possible in power stage configurations.

Brian Casey: Faster and more powerful CPUs will result in both smarter and dumber drives. The traditional motion control command interface of an analog 0-10 V velocity command was characterized by a distribution of the CPU processing power between the motion controller and the servo drive.

The most significant trend is the more powerful CPUs, combined with the acceptance of high speed digital interfaces like SERCOS, to allow the processing power to be distributed to the servo drive to manage loop closure for each axis. In Rockwell Automation's integrated motion architecture, this allows a single processor to be used to perform both the machine logic and motion control path planning in one program, simplifying the overall system for the user. And the ability of the drive to manage the current, velocity, and position loops results in an overall improvement in system bandwidth and ability to react to external events.

In some cases, more powerful CPUs are also allowing one or even two processors to be used to manage the path planning and perform the loop closures sending a simple torque or PWM command to "dumb" drives. These "centralized" control systems are often limited in the number of axes and processing speeds will be slowed as additional axes are added to the system.

Edward Steiner: Faster and more powerful CPUs will always be used in new products. From a marketing standpoint you need the latest technology to get noticed. The question of smarter or dumber drives is really a control architecture question: central or distributed control. The marketplace provides both at the present time and I don't see that changing. There are application strengths for both types of control architecture and, until one emerges with significantly lower cost, both will survive.

Curt Wilson: The development of faster CPUs pushes toward "dumber" drives, because it is more cost-effective both in terms of hardware cost and software development to lump as many calculations as possible in a single processor than to distribute them among multiple processors with complex communications protocols between the processors. However, the desire to reduce the number and length of wires in a system is simultaneously pushing toward smarter drives, each placed close to their motors, with a "skinny" cable connecting them to the controller with low bandwidth communications.

In other words, there is no single trend. Starting from the traditional (analog) velocity-mode servo drive, one trend has been to successively strip functions from the drive and move them to the central controller, resulting first in torque-mode drives, then "sinewave" drives, and now "powerblock" drives. Another trend has been to add a digital positioning front end to the drive, either to make it standalone-capable, or as part of a highly distributed system. The options just keep multiplying, with no end in sight.

Many people do not realize what a large percentage of servo drives currently manufactured and shipped are dumb power blocks. This is because most of these are not sold in the merchant market, but utilized in the manufacturer's own systems. Most of the world's largest CNC manufacturers -- e.g. Fanuc, Siemens, and Heidenhain -- utilize power block drives almost exclusively in their systems. The completely centralized processing is optimum for the tightly coordinated control required here -- it provides the highest performance at the lowest cost, with complete flexibility to share information between axes as needed.

Distributed smart drives have their place for relatively uncoordinated control. However, many users have gone down this path without realizing the limits they are placing on themselves with this approach. Smart drives linked by a Fieldbus have caught a lot of attention lately, but many people have abandoned them after investing a great deal of time and effort due to the difficulty in achieving slight coordination between axes -- even just to the extent of making sure that a fault on one axis can be sure to stop other axes in time.

Jayson Wilkinson: It is difficult to say how more powerful CPUs will affect drives. One of the trends we are seeing is a trend toward more highly integrated systems. Systems requiring integration between multiple components may still take up enough resources to make motion control on the CPU difficult. However, motion controllers based on DSP technology as well as smarter drives can effectively move the intensive calculations and monitoring required for motion control away from the CPU. However, because DSP-based motion controllers do not require smart drives, it is difficult to say whether any increase in the power of the computer CPU will have any major effect on the intelligence in drives.

Joseph Martin: More powerful CPUs will do both -- make drives smarter or dumber. They will give the manufacturer the option of placing the intelligence of the system closer to the actual operations or in a centralized spot. The manufacturers will be the ones who choose based on their particular expertise.

Christopher Fournier: Smarter. Drives will continue the trend away from analog to digital. Faster, low cost CPUs will be used at both ends of the drive spectrum. The type of drive will depend on whether or not a motion controller is present. For some applications, enough intelligence can be built into the digital drive to do complete position control as well as some basic I/O control. However, most machines need more control capability to handle multiaxis coordination or higher I/O counts, user interface control, network communications, etc. In these applications, where a motion controller is present, the "smarter" drives will control a digital current loop and communicate via a digital network to the motion controller. This digital networking solution offers a very low drive cost without the limitations and risks of trying to centralize the current loop or commutation control in a central motion controller.

What is being done to improve accuracy/precision to accommodate markets such as fiber optics (nanometers) and semiconductors?

Michael Backman: We see the word "nanometer" thrown around too easily these days. Achieving 0.01um (10 nanometer) and better precision is extremely difficult in practice, particularly over larger travels. If you don't have six foot thick isolated concrete floors in a temperature controlled clean room with acoustic barriers and specialized metrology equipment, then you likely haven't discovered how to even measure a nanometer, much less achieve that precision in positioning. Are you really confident in publishing a system spec roughly equal to the diameter of a few water molecules? I hope you don't base that on your theoretical electrical resolution!

This level of precision requires different thinking. Employing extremely stiff, well-damped and thermally stable structures, zero cog actuation, zero friction bearings, and unique control algorithms aren't enough. We have surpassed the capabilities of machined dimensions and tolerances. Remember the basic six degrees of freedom? For a one-axis positioner, five of those (straightness, flatness, roll, pitch, and yaw) used to be "built in" to the design. When you find yourself dynamically controlling six axes for a single axis application, you'll start appreciating the challenge.

Jayson Wilkinson: When talking about motion on a nanometer scale, many different factors come into play to contribute to the accuracy and precision of the system. The motion controller, the drive, the mechanics of the system, and the feedback devices all have an important role to play in delivering accurate positions. Some of the important things vendors are doing to help increase accuracy in systems are reducing noise on the drive, creating higher resolution encoders, creating more accurate actuators such as piezoelectric motors, and providing backlash compensation or dual-loop feedback on the motion controller.

Brian Casey: Improvements in affordable high-resolution feedback devices have made a big difference, however this does nothing without good amplifier technology, as well as improvements in the machine mechanics. In many cases the elimination of mechanical transformations and the movement toward direct drive linear motors has raised the bar in both of these market segments.

Curt Wilson: There are advancements on many fronts here. Mechanically, the spread of linear and direct-drive motors, plus air-bearing stages, are removing many sources of mechanical errors. In sensors and controls, the use of sine-wave encoders (often linear scales) with interpolation electronics achieving 4000 or more states per line is providing unprecedented resolution and accuracy. High-speed DSP controllers, especially those with fully digital control to power-block drives, minimize delays and noise sources that have limited performance before. Combined with the reduced "quantization noise" from highly interpolated encoders, unprecedented servo performance is being achieved, permitting highly accurate control that is also very fast control.

* * *

A motion forum wouldn't be complete without bringing up SERCOS. How strongly are you supporting it? What is its future?

Pat Dvorak: At Bosch Rexroth we have been one of the leading manufacturers producing products around the standard from its inception. We remain convinced that SERCOS is the only practical standard on the market today. SERCOS has successfully withstood attacks from many competitive protocols and continues to make great strides. Some recent advances are:

• The release of the SERCON 816 ASIC that yields 4x greater speed and lower cost;


• Development of a new conformance testing lab and tools to bringing full multivendor interoperability closer;


• Establishment of the Center of Expertise at the University of Akron with courses on SERCOS and a help line.

Joseph Martin: Giddings & Lewis sees our shipment of motion control systems utilizing SERCOS communications doubling every year. In our experience, SERCOS is as truly an open network as we have experienced in motion applications which successfully combine our Centurion servo amplifiers and other suppliers' servo amplifiers operating on the same SERCOS ring to form a complete solution. We are fully committed to SERCOS and offer it in our rack mount PiC controls, standalone MMC controls, and MMC for PC controls, as well as our Centurion servo amplifiers. With the release of the SERCON 816 interface, quadrupling the SERCOS communication rate, and the work of the SERCOS standards group on uniform interoperability testing, we see SERCOS continuing to grow far into the future.

Michael Backman: In the semiconductor, electronics, and photonics equipment markets, SERCOS has not been widely adopted, and we currently see no trend in that area.

John Walewander: Compumotor continues to be an advocate of all open standards. Compumotor strongly believes that standards provide comfort and migration paths to customers that help further the capabilities of motion control components as a whole. SERCOS is supported for these reasons, but with reservation. The majority of Compumotor servo products sold each year are rated at less than 1kW. This is consistent with the market as a whole. For servo products of this power range, it is impractical to burden the product with the high cost of SERCOS hardware and software. Until there are changes in the chip cost or ability to use other hardware with SERCOS software, SERCOS will remain an important but not a dominant protocol.

Christopher Fournier: We do not support SERCOS. In our view it is an overly complex and costly approach for networked motion control. Before the emergence of Ethernet and other mainstream high-speed digital networks, SERCOS was a valid choice, however when you look at the options today it doesn't make sense unless you have to stay compatible with a legacy system.

Groum Gedle: Automation Intelligence is one of the two founding members of SERCOS NA (North America). Our CEO, George Kaufman, is the president of SERCOS NA. AI's multiaxis controller is SERCOS based. We are fully committed to growing the SERCOS technology as the most preferred motion bus in the motion control industry. There are over 70 manufacturers worldwide that make SERCOS-based products. I believe the list will continue to grow and more enhancements in the SERCOS technology will follow. SERCOS has been around for over ten years and I believe the protocol has matured to support various vendor products.

Jayson Wilkinson: Currently, we are waiting to see how important SERCOS will become in the motion control industry. We have seen that it has some very appealing characteristics but also have seen that it may not be good for every application. Applications requiring very fast communication between the motion system and other systems, such as a vision system, may not be ideal for SERCOS. We view SERCOS as yet another bus that we may choose to support if demand for it raises enough to justify it.

Curt Wilson: We are not presently supporting SERCOS. Its heritage as a low-bandwidth interface not originally capable of closing loops centrally has resulted in a very complex protocol and expensive drives to support this protocol. Many SERCOS drives have both a microprocessor and a DSP just for a single axis! SERCOS has not gone away, but it is not taking over the world, either.

Edward Steiner: IIS is fully supporting SERCOS. We have several SERCOS products and Jim Carter from IIS is the chairman of the US SERCOS technical working group. All our SERCOS products use the new high speed SERCOS chip. In my opinion SERCOS is the only viable servo bus in the international market today. SERCOS delivers the promise of multivendor interoperability that really works. There are other servo buses and some non-servo buses, used for servos. They are technically viable, but without multivendor and strong standards, support won't survive. The days of non-standard, proprietary or limited vendor support are gone.

Brian Casey: Rockwell is 150% committed to SERCOS. We have several active members in SERCOS N.A., and Brian Casey is the Marketing lead on the IGS board. Rockwell is utilizing the technology for its integrated motion offering, and contributing to the further technical development of the standard.

As the only widely adopted standard dedicated to the current and future requirements for motion control, SERCOS is viable now and into the future. The SERCOS group is reviewing future technologies for applicability in this space, and intends to integrate complementary technologies as they emerge. The delivered benefit is a bona fide communications solution for motion control applications, not simply a particular technology.

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Will the trend toward turnkey motion systems continue?

Christopher Fournier: All else equal, customers would prefer to buy as many components as possible from a single supplier who can also offer integration support services. That being said, in the motion control market we are seeing a bit of a break in this trend as customers become more sophisticated. For example, in the stepper market it has been very common for customers to buy motors from one vendor and drives from another due to the simplicity of the interface. We are now seeing this trend in the servo market as well, especially with OEMs, because integrating a servomotor with a drive is no longer considered a "black art." Since most of our customers are controlling more than just motion, e.g. I/O; user interfaces; vision; enterprise connectivity; etc., we have not seen a significant increase in the number of requests to supply complete motor and drive systems with our controllers.

Groum Gedle: I believe there are two types of customers for motion control. On one hand, there are customers that have in-house expertise to do machine integration and are interested in purchasing only the components they require for their applications. For these types of customers, a turnkey solution is not attractive. On the other hand, there are many end users that are not interested in doing the integration work. They prefer a turnkey solution from machine builders and system integrators. Automation Intelligence has system integration capability to serve these types of customers.

John Walewander: No. We believe a new level of system solution is being created and will detract from the attractiveness of turnkey solutions. Turnkey systems were very important when motion controllers were very hard to use and the level of knowhow that was needed for a successful application was extremely high. Because of standardization in the industry, and due to increased awareness and training on motion systems, customers that previously wanted a turnkey system will be able to do it themselves. By doing the integration themselves, customers will be able to greatly decrease their project costs by eliminating the external labor, overhead, and profit. For this type of approach customers will be looking for suppliers/partners who can supply them a wide variety of solutions and also be able to provide the "technical value added" necessary to support the customer in his modest integration. Parker is positioned to supply this type of solution and will be able, with the support of our ATCs, to increase the number of customers who can do it themselves. The customer will always be able to enlist the contracted support of the ATC if and only if it is necessary.

There has been much downsizing as automation and competition have lowered costs and reduced prices. Are we seeing this strong price competition in the motion control industry?

John Walewander: The motion industry has consistently been attracting new competition both domestically and abroad. The threat of over-capacity has forced many companies in the motion market to increase the level of price competition. In addition, the recent economic downturn has increased the level of collective inventory of motion suppliers, which has added to the already increasing price pressure. Luckily, the Compumotor business model has not caused an increase in inventory, but the climate of the marketplace continues to change. Over the last five years, servo drives have continued a march toward commoditization that has resulted in a 50% drop in standard pricing over that period. The trend will continue; however, the pace of price decrease will slow.

Christopher Fournier: The price competition in the motion market is greatest in the motor and simple drive area. There are several suppliers offering virtually the same thing and the primary way to compete is price. As more intelligence and functionality is added to the electronics, it increases the value to the customer and suppliers are competing on non-price attributes.