Machine tool builder exeron is convinced that OPC UA is the way forward. The specialist in electrical discharge machining (EDM) has developed a communication solution based on the open IEC standard. We sat down with software specialists Michael Lamparth and Paulus Kolb from exeron and Sebastian Sachse, B&R's technology manager for open automation, to find out more about the OPC UA project and what plans and expectations they have for the future.
Sachse: OPC UA is the solution to one of the greatest challenges in modern manufacturing. Whether you call it Industry 4.0, Industrial IoT or Smart Factory – the advanced manufacturing systems we envision for the future will only be possible if all the components in a production line are able to communicate over a uniform network. From individual sensors up to the ERP and DCS level, the only way to achieve the level of transparency required for Industrial IoT applications is by bridging the gap between IT and OT.
Sachse: That's exactly the point: there are too many protocols. On a typical plant floor, you've got machines from a variety of manufacturers, each with their own control systems and fieldbuses or Industrial Ethernet networks. Even if these machines are operating independently of one another, you're looking at added time and effort when it comes to commissioning and maintenance.
Sachse: Exactly. In this scenario that would be virtually impossible. You'd need to hire expert personnel and spend time and money programming and maintaining countless gateways and interfaces. What's more, as soon as you need response times in the real-time range – to synchronize a robot with an injection press, for instance – then you're completely out of luck.
Kolb: We're looking to cut down on the number of interfaces we have to support. Our first step was to focus on communication within the machines themselves, but the potential for OPC UA in our industry is much bigger than that. In the medium to long term, our goal is to play an active role in developing and promoting standard interfaces based on OPC UA for both M2M communication as well as for integrating with shop floor data collection and ERP systems.
Kolb: Standardizing the interfaces frees up our internal resources and allows us to redirect that energy toward features that differentiate our EDM and milling solutions. We're not alone in this approach either – a uniform interface really is a win-win situation for everyone involved. With OPC UA, the right solution for implementing them is already available.
Kolb: The first application will be to connect the HMI system to the CNC controller on our EDM line. Certain requirements unique to EDM processing prevent us from using universal controllers. Instead we developed special CNC controllers and – for lack of a better alternative – created a proprietary interface to connect with our HMI systems. Over the course of 20 years, this approach has resulted in a whole range of interfaces that exeron has had to develop and support with our own resources. The same goes for the diagnostics and maintenance options.
Lamparth: Our first step was to analyze our proprietary interface and define the necessary data objects. Based on that, we evaluated how these objects and the required functionality could be implemented with OPC UA. We gained valuable insight by evaluating similar approaches taken with the CORBA standard and by the ISW at the University of Stuttgart. Then we looked into how the whole thing could be done with B&R solutions. The result of our collaboration was a functioning prototype.
Kolb: The increasing level of automation we're seeing from our customers means the number of interfaces that potentially need to be supported – throughout the line and beyond – is growing as well. One example is the scanner module we developed to equip our tool/workpiece magazines for 24-hour operation. Over the years, we've defined numerous interfaces to accommodate different scanner units and magazine types in the machine control and DCS systems. We'd now like to unify those with OPC UA as well.
Lamparth: The other thing is that we're not the only ones who offer these types of magazines. And since the other machines also use proprietary interfaces, manufacturers of cell control systems are forced to deal with a huge variety of scanner units and their respective interfaces. It stands to reason that all parties involved will benefit from an interface that provides information such as tool position in a uniform way. An OPC UA profile would lend itself to this.
Lamparth: We've taken on a pioneering role in this, and have developed a scanner interface based on OPC UA that we use internally. It could serve as a blueprint for a profile, which ideally would then be standardized by the OPC Foundation. We're convinced that this would be met with great interest on the part of control system manufacturers. Existing systems can of course be connected via a gateway, but going forward our devices' internal communication will all be OPC UA. We realize, of course, that machine operators aren't going to start listing this kind of interface in their specifications until it's been around and has established itself. But then they'll start asking for it.
Sachse: There are a number of reasons. For starters, OPC UA is an independent and widely-recognized standard that connects the worlds of production and IT. It also offers built-in security functions that ensure data is transferred securely and reliably. And then there is one very decisive difference: OPC UA doesn't just transmit data, it transmits information.
Kolb: Excellent. Current trends like Industry 4.0 and IIoT and the ongoing OPC UA developments – like open sourcing the stack – are dialing up the pressure to develop and implement standardized interfaces at every level of the automation pyramid. Prior to OPC UA there was no standard that was simultaneously open, secure, hardware independent, cross-platform and scalable. So, for the first time, OPC UA makes it possible to have uniform interfaces from the ERP level down to the fieldbus level. That unleashes a whole new dynamic.
Lamparth: It's hard to make a real assessment there, because the standard is still evolving. We would love to see that field-level determinism though. It would be great to see it in standard interfaces for drives that would allow us to switch effortlessly between drives from different manufacturers. For now, we will continue to rely on protocols like POWERLINK that are able to transmit 150 bytes of cyclic process data highly deterministically and synchronously within 400-microsecond cycle times. OPC UA can't do that yet, but we'll see where the ongoing developments take us.
Software specialist, exeron
"Prior to OPC UA there was no standard that was simultaneously open, secure, hardware independent, cross-platform and scalable. For the first time, OPC UA makes it possible to have uniform interfaces from the ERP level down to the fieldbus level. That unleashes a whole new dynamic."
Software specialist, exeron
"Standardizing the interfaces frees up our internal resources. With the OPC UA connectivity provided by B&R, the right solution for implementing them is already available. The result of our collaboration was a functioning prototype."