A decade ago, communications in machines took place on a point-to-point basis. If you were building a multi-axis system, you would have to wire 15 wires per axis from the drive to the controller. If an axis faulted, the system would only return a single digital I/O point indicating a fault. Discovering the source required interrogating the drive¾no matter where on the machine it was located¾then spending a significant amount of time troubleshooting. The development of industrial Ethernet changed that model, and those of us working in machine automation have never looked back.

All those wires involved in point-to-point wiring created significant problems, especially as axis counts rose. They added complexity, took time to install, required space, and cost money. In addition, they were a nightmare to troubleshoot, especially in the case of intermittent faults (and wiring faults are almost inevitably intermittent). Early fieldbuses represented a significant improvement over point-to-point wiring but had limitations in terms of speed and ease of use. Interfacing devices designed for different field buses required custom firmware. Speed restrictions limited the number of devices that could be interconnected, practically speaking. Industrial Ethernet provided a major upgrade.

With Industrial Ethernet, a single cable is all that is necessary to connect master encoders, drives, and controllers. Instead of having to hook up a laptop to each device individually in order to troubleshoot, you can just connect to the master and interrogate the entire network. Rather than getting a single digital I/O point back after a fault, you can review and interrogate the drive to find out exactly what happened.

The Many Flavors of Industrial Ethernet

The chart above describes five common industrial ethernet approaches and their topology.

Ethernet was initially developed for computer networking. As a result, it was packet-based and built around best-effort delivery. A packet might be delayed simply because of traffic management. Packets might be lost, as well. This isn’t a problem when it involves a print job or an e-mail. If it involves a drive command or feedback for a 100-axis printing machine, however, determinism becomes a huge issue. Packets need to get where they’re going in the order and in the time frame required. This makes determinism a major concern in the design and execution of industrial Ethernet protocols.

At the beginning, there were a number of contenders in the industrial Ethernet space, including CIP, EtherCAT, Ethernet/IP, ProfiNET, and Ethernet POWERLINK, not to mention more conventional field buses like CANopen, DeviceNet, and Profibus.

Common Industrial Protocol (CIP). This media-independent industrial automation standard is based on a producer-consumer model. CIP lends itself to various hierarchies, including master-slave, target-originator, and slave-multimaster. It is an object-oriented protocol that describes the operating and communications characteristics of each device. The CIP family of standards includes CIP Motion, which enables drive control, and CIP Sync, which defines a distributed clock.

DeviceNet. A digital fieldbus, it is designed for master-slave control and centralized architectures or peer-peer control over distributed architectures. The protocol can link 64 nodes at up to 500 kbps. It’s not a motion-specific protocol but can be used in simple systems, particularly for tasks like feedback.

EtherCAT. Based on a master-slave architecture, EtherCAT supports deterministic, highly synchronized motion. An EtherCAT telegram goes from the master to each attached node in sequence before returning. It can introduce a certain amount of latency as a result, but the speeds are so fast (100 Mbps) that it is not an issue for practical purposes. EtherCAT operates at cycle times of 100 µs and jitter of 1 µs or less; it can connect more than 65,000 separate nodes.

The EtherCAT protocol defines the physical layer and the data layer of the network. For the network layer itself, EtherCAT supports multiple different communications profiles, including CANopen over EtherCAT (CoE).

Ethernet POWERLINK. A real-time protocol deterministic enough for motion control, Ethernet PowerLink can also send non-real-time data over TCP/IP frames. Built around the master-slave architecture, ethernet PowerLink uses a master clock to synchronize communications. A polling message timed to the clock both sends information to the slave nodes and interrogates them for their replies. It operates at 100 Mbps, with a minimum cycle time of 200 µs and a jitter of about 20 ns. Each master (managing node) can control up to 259 nodes, each of which can act as a master in its own right.

ProfiNET IRT. Based on a producer-consumer model, this uses a master clock to schedule communications at asynchronous time frames. ProfiNET uses its own ether type, which enables motion messages to avoid the TCP/IP transport layer and go directly to the application layer. As a result, it is able to support hard-realtime communications.

Each protocol has its pros and cons. In many cases they are proprietary, and in most cases, they don’t play well with one another. The exception is CIP, which works well with DeviceNet and Ethernet/IP, but that is because they all originated with Allen Bradley.

EtherCAT Leading the Charge

EtherCAT is one of the more popular ethernet connections available for networking automation products, computers, and sensors. (Image credit: Beckhoff)

To find out why Motion Solutions believes that EtherCAT is leading the way, we asked Bill Lackey, vice president of automation at Motion Solutions, why the company prefers it over other type of connections.

How did EtherCAT gain the advantage over other connection types?

From an engineering standpoint, dealing with all these protocols has been more than a little frustrating. As the system designer, you want to use the best technology for the application. You don’t want to be locked into a proprietary protocol because that is the only option available for a given motor or drive¾or because the end-user already has that protocol on some of their installed base. So, back in the early days, those of us in the OEM community did the best we could and waited for the competition to shake out.

From where we sit, EtherCAT has won the industrial Ethernet derby. The EtherCAT Technology Group includes hundreds of members. There are commercially available EtherCAT steppers, sensors, drives, controllers, encoders, switches, and even safety. At a series of regular meetings called PlugFests, manufacturers test out their equipment for interoperability. The result is a user-friendly suite of solutions.

What are some of ways you and Motion Solutions uses EtherCAT?

The EtherCAT protocol supports highly deterministic and flexible control. Our team at Motion Solutions recently built a 100-axis motion system designed for high-volume testing of consumer electronics products. They wanted to be able to vary the number of devices under test rapidly and without any additional effort. They wanted to be able to modularly take off 24 axes at a time and make them modular. If you were to try to wire that type of system discretely, the bundle of wire to make it work would probably be four inches in diameter.

With EtherCAT, it was easy. We connected the components with an EtherCAT cable. We supplied power to the drive and the customer could power it up with three sets of 24 axes or zero sets of 24 axes—it doesn’t care. There are many applications where EtherCAT is best suited to handle applications that require coordinating multiple axes.

How versatile is EtherCAT with other network architectures?

In the OEM community, we need performance and flexibility. We don’t want to be locked into a single supplier. EtherCAT delivers not just the performance but a broad choice of components from a deep and vibrant supplier ecosystem. Just as important, the members of the ecosystem work to ensure interoperability. When you buy EtherCAT components from two different vendors, you don’t have to wonder whether they will work together. Engineering at its heart is about choosing the best technology for the job.

View the original article and related content on Machine Design

The 2008 global downturn changed the economics of manufacturing. To stay in business, companies slashed budgets and cut staff to operate as leanly as possible. Now that the economy has recovered, the focus is shifting from survival mode to market leadership.

The problem is that the staffing cuts that helped companies stay solvent may have left them without the in-house engineering talent needed to develop the innovative products that will move them ahead of the competition. The solution? Outsource.

Although outsourcing is more commonly associated with manufacturing or service offerings like customer care and payroll, outsourcing engineering is an increasingly common way to bridge the skills gap. It is particularly effective in the case of complex support technologies like motion control.

Motion control is often essential to the performance of a product, and yet frequently has little to do with its true function. Outsourcing the automation subsystems to motion specialists creates a sort of virtual engineering team that ensures the product operates as desired, while freeing the in-house engineering team to allocate its efforts where they provide biggest competitive advantage.

As with all things in engineering, outsourcing is not a universal solution. If an organization has an extended development timeline, deep expertise, and widely available resources, keeping the project in-house may make the most sense. In many other scenarios, outsourcing may be the best approach for cost control, product quality, and time to market.

Here are five reasons to consider outsourcing your motion control engineering:

1. Lack of In-House Motion Expertise

The most obvious candidates for outsourcing are companies whose products may require automation, but whose core value proposition lies outside of motion. A DNA sequencer, for example, applies precision motion to rapidly position a pipette over a series of DNA wells. That’s not the key differentiator, however.

What matters to the company in the marketplace are the chemistry and the analytic software that enable the instrument to outperform the competition. By outsourcing the engineering of the XY stage, the organization can devote more development hours to the biology and science aspects of the machine. The outside team becomes the mechanical engineering extension of the company.

2. Performance Goals that Exceed Capabilities

Even organizations that have been designing and building sophisticated motion control systems for years may at some point reach the limit of what they can achieve performance-wise. That is when outsourcing to a group that specializes in motion control can make a big difference.

Recently, a customer who was having difficulty meeting spec on a product reached out to our company. The customer wanted to order a specialty bearing to hopefully solve the problem. When our engineers learned more about the system, however, we realized that the issue wasn’’t caused by a single component. The problem had to do with the overall design.

The customer brought the machine to our facility, where we could analyze it using specialty equipment that they didn’t have. Our team identified several small but crucial issues. By making minor modifications that same day, we were able to improve system performance more in a few hours than the in-house team had been able to over the previous six months.

This highlights two core values of outsourcing engineering: Not only can it enable an organization to achieve better performance than it can accomplish alone, but it can deliver that performance significantly faster.

The stats above show the countries with the most engineering graduates. (Image credit: Statista)

3. Tight Development Cycles

Time to market has a huge impact on the profitability of a product over its life cycle. Particularly in sectors like medical and semiconductor, being first to market creates great customer loyalty simply because the initial product is familiar. Companies can’t afford to invest 12 months in design and testing; they need to develop and release new products in a short period of time to keep up with the competition. This is where outsourcing engineering can make a big difference.

Organizations that provide engineering services frequently have portfolios of motion systems that can be easily tailored to a particular application. A company designing a novel automated patient bed, for example, can take advantage of the expertise of a motion partner who has developed dozens of beds.

By making a few modifications to a proven design, the motion specialist can help the medical device company roll out a new system in a month or two rather than a year—and with a very high confidence level that it will work, based on data from field-tested systems.

Outsourcing engineering also speeds customization. In one recent project, a customer wanted to add an additional axis to an already complex machine. There was no question that, given enough time and resources, the in-house engineering team could make the modification on its own. The problem was that all of the engineers were hard at work on the main platform.

Rather than delay getting the product to market, the customer asked our engineering services group to develop it as a subsystem that could basically be bolted onto the machine at the last moment. The machine builder was able to offer its customers additional functionality without losing first-mover advantage.

4. Need for a More Manufacturable Device

There can be a world of difference between a working prototype and a production-ready product. Minor design elements like alignment features can significantly improve ease of assembly, quality, and production throughput. Engineering for manufacturability can also make a difference in overall system operation.

We worked with an equipment builder who placed a highly effective but failure-prone component in the heart of its machine. The machine delivered high performance, but had the potential to be a maintenance headache once it was in operation. Our team redesigned the system so that the component could be replaced after moving just one part. This design modification would enable the asset owner to replace a failed part and be up and running in hours instead of days.

5. Cost Concerns

At the end of the day, business is about profitability. Manufacturers constantly seek ways to control costs by reducing inventory, manufacturing space, labor hours, etc. Motion system design can impact all of these factors and more. Organizations with motion expertise can perform cost-down engineering to reduce the number of parts, speed assembly and test, and limit equipment demands.

If the partner offers manufacturing services, as well, things get even simpler. Instead of writing eight to 10 purchase orders and taking up factory space and labor hours to build a subsystem, the manufacturer receives the complete assembled and tested subassembly.

Design of motion control systems is as much art as science. For OEMs who need performance they can’t achieve alone—whether through limitations of experience, time, cost, or other factors—outsourcing provides an effective solution.

View the original article and related content on Machine Design