Making electrical positioning easy to select, easy to connect, easy to configure

Author : Warren Harvard, Product Manager for Electric Drives at Festo

05 December 2017

With all the challenges that machine builders face over the selection, connection and configuration of electromechanical drives solutions, this piece sheds some light on how to make the process easier...

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Making electrical positioning easy to select, easy to connect, easy to configure What are the biggest challenges currently facing machine builders? For special purpose machine builders, being able to specify solutions quickly and easily, with total confidence in their performance, is key to winning business efficiently. For replicating machine builders, the challenge is to find a way to build standard solutions that can be re-configured easily and cost effectively to meet customer standards in terms of fieldbus and connectivity protocols. In both cases, it’s a highly competitive environment. Cost is critical – but it’s often those who respond first with a quote who gain the advantage.

There is, however, an inherent conflict between reducing time and reducing cost. Shopping around multiple suppliers can identify lower cost components; but the all-important final price often masks the associated engineering sourcing, procurement, design and compatibility costs.

Building a solution using multiple components from different suppliers is inherently complex, time consuming and risky. There’s always potential for mistakes to be made – particularly when trying to ‘marry up’ different manufacturers’ data, frequently presented in different formats and units. The potential for issues to arise around compatibility and connectivity is high, and with multiple suppliers involved, it’s often unclear where ownership of that risk lies.

How does this affect end users?

Time pressures and desire to avoid risks can lead to disadvantages for end users. It reduces the opportunities for machine builders to consider all the options and add real value at the design stage. Instead, the tendency is to stick with a proven specification and adopt a ‘belt and braces’ approach.

This can mean that the recommended solution is not optimised, may be over-engineered, and is more expensive than it needs to be. As a result, the end user can get a less efficient, more complex solution than necessary – creating potential service, maintenance and lifetime cost issues.

Can you give an example?

Electrical positioning systems are a good example. They are commonly used in almost any machine that needs to position and move objects. Typically consisting of a positional controller, motor, gearbox and mechanical axis, cables and connections, overall system performance is a result of the combined performance of the individual components. Machine builders frequently source different elements from multiple suppliers – introducing questions around performance, compatibility and connectivity.

Because of this, it’s often easier, quicker and safer to stick to previously-used solutions, rather than search for new ones. The effort and risk involved in deviating from known solutions is a real barrier to cost and performance optimisation. As a result, machine builders often choose to stick to a known servo electric system that provides top-end performance, even when the application doesn’t require it – and when there are other, more cost-effective technologies that can be used. For example, if dynamic movement requirements are not onerous, closed-loop stepper motor technology offers the same control capability and can manage similar loads to servo systems, but at lower cost.

What can be done to improve this situation?

Suppliers need to make it easy for machine builders to match components in order to deliver the required performance: think ‘easy to select, easy to connect, easy to configure’.

Manufacturers of electric drive components can play an important role by providing the tools and products to make it easier for designers and machine builders to make the right choices. There needs to be greater understanding of designers’ needs by component manufacturers, so that they can provide fast, knowledgeable support throughout the specification, buying and machine-building process.

What does Festo have to offer the electric drives market?

Our overall approach is to focus on the needs of the machine builder. We do this by supplying all the elements in the control chain needed to make the solution work – both mechanically and electrically.

The result is an integrated and joined-up solution: easy connectivity, guaranteed system performance and compatibility, plus technical and customer support – all from one source. And because we offer all the elements, machine builders and designers can take advantage of a free simulation tool that provides a range of technical solutions based on the application requirements. The results provide guaranteed performance, known costs, and critically, the opportunity to make rapid, optimised risk-free decisions.

A good example of this is our Optimised Motion Series (OMS). We used our expertise to develop a total package that offers a cost effective solution for many positioning applications. Based on closed-loop stepper motor technology, the Optimised Motion Series of electric drives has been developed to provide easy-to-use, multi-position control at a highly focused price point. This way, OEMs and machine builders can order a complete electric drive system using one product code and receive all the components they need, including the cables, connectors and gearbox – delivered in one box. Because you are dealing with one supplier for all the components, compatibility is guaranteed.

What about connectivity?

The OMS Series uses Festo technology to facilitate connection to various end user protocols. Machine builders can therefore design a standard electric drive system that, with a simple, inexpensive change to the connectivity node, can communicate directly with a wide range of systems, including:

• I/O-link

• CANopen

• DeviceNet

• EtherCAT



Even the programming is supported with simple, modern, web-configuration tools. All parameters are downloaded from the Festo web server, rather than having to be entered manually; this significantly reduces programming time and potential for error.

The Festo advanced CMMO stepper technology enables lower cost motor technology, but with advanced control capability, including force and position control – delivered in a smooth and optimised motion profile. Open-loop control is the lowest cost option; but where accuracy and continuous monitoring is required, encoder feedback enables the system to operate in a cost effective and full-closed loop servo mode.

What about support with specification and commissioning?

Festo has a freely available online software tool called Positioning Drives, which helps OEMs and machine builders select the optimum electric drive package for their application.

Upon entering the application details, the software comes up with a range of technically-matched solutions. The software’s inbuilt mechanical knowledge and understanding takes into account the mechanical axis – whether piston rod, rodless gantry, cantilever-based linear drives or guided rotary tables – and provides the optimum product choice in terms of bearings, guidance and application demands (such as mass, centre of gravity, off-sets, velocity, and so on). Electrical compatibility is assured, because once the optimum mechanical drive is selected, the motor and gearbox are matched to the performance requirement.

The Positioning Drives software provides information about the safety margins offered by the proposed solutions, so the designer can make an informed decision – making electric drive selection quick, simple and risk-free. There is also simple, free access to CAD drawings in all standard native formats, alongside electronic datasheets for easy technical file compilation, performance assurance and a single complete system price – so all the information is available in one place.

Once the machine builder has taken delivery, the chosen OMS package can be assembled out of the box, using a simple Allen key. Because all the components come from one manufacturer, the mechanical interfaces are designed to work together to provide secure, aligned axes; this way, there is no need for additional, expensive brackets and adaptors. When installation is complete, Festo’s free web-configuration tool makes it fast and error-free for the controls or commissioning engineer to both set up and prove the solution.

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