The foundation for intelligent sensors and actuators

16 June, 2017

As industrial devices are becoming more connected, boosted by trends such as the Industrial Internet of Things (IIoT) or Industry 4.0, factories are increasingly using industrial networks to make their sensors and actuators more intelligent. This is largely driven by the need for better performance, flexible manufacturing and the desire to integrate factory installations with IT systems.

Communications enabled devices are used extensively in the modern factory to control industrial processes or machines. Microprocessor based systems provide advanced functions, including analogue monitoring, control and high-speed motion control as well as data sharing over communication networks – so which of the various industrial networks available on the market today are being successfully utilised in the implementation of the IIoT for pneumatic motion control?

More and more manufacturers have their own ideas and interpretations of what a ‘smart factory’ is and what they want it to do for them. A common theme is often the need for embedded components to have additional intelligence, thereby enabling machine-to-machine communication and reaction. All of these ideas eventually come down to more practical aspects such as system architectures and how the multitude of new sensors – and an increasing number of actuators – will communicate via the network.

Industrial networks are used for process control, monitoring or both. Industrial network protocols can be thought of as a set of rules that the system must adhere to which governs the language, media and topology of the network itself.

Selecting the right network is always going to be about what’s most important to the manufacturer. The system topology is also a key consideration for factors such as redundancy, future expandability, ease of implementation and what kind of special hardware is required to run the system.

IIoT driving changes in the market

Ethernet networks are rapidly gaining popularity. Many of these networks and protocols are specifically designed for industrial applications, and some of the main benefits include integration with the IT infrastructure, Internet connectivity and remote monitoring.

Many of the Ethernet networks and protocols, such as PROFINET IO, EtherNet/IP, EtherCat, Modbus TCP, have been around for the past 15 years, but until now the prohibitive cost of installing these systems had limited the scope of their applications to those requiring the highest levels of sophistication. As a result, more economical fieldbus networks such as PROFIBUS DP, DeviceNet, CANopen, AS interface have been popular in the past for less complex operations.

However, the trend we are seeing now, in all types of industries where process automation is applied, is that the traditional fieldbuses, such as PROFIBUS DP, DeviceNet and CANopen, are slowly getting squeezed out of the picture, both with the cost of Ethernet networks and protocols coming down and the rise of emerging technologies in the market, such as wireless networks and open communications protocols.

IO-Link: watch this space

One of these relatively new open communications protocols, IO-Link, could be the next significant industrial network protocol being a perfect local extension of a superior Industrial Ethernet network. Started in 2008 by Siemens, it is the first IO technology for communication with sensors and actuators to be adopted as an international standard (IEC 61131-9), meaning that devices can be integrated in the same way in all commonly used fieldbus systems and automation systems, right up to enterprise resource planning (ERP) level.

The high-performance point-to-point interface is based on the 3-wire connection that has all the simplicity of a plug-and-play installation. IO-Link uses standard, non-shielded cables to connect slave devices to the IO-Link master. This reduces the cost of cabling by a factor of five compared to protocol-specific cables.

Each device’s configuration can be stored and downloaded into a new device if a replacement is needed, with no programming required.

The key to unlocking the power of these intelligent devices is in making this diagnostic information easy to access. IO-Link allows for cyclic data exchange capabilities so a programmer can easily send the valuable information directly to where it needs to go, either to an HMI screen, a signal light, or a maintenance request. If sensor or actuator parameters need to be changed or calibrated, that can be done remotely; even while the production line is still running, and that means shutdowns and stoppages can be avoided. If sensor or actuator parameters need to be changed or calibrated, that can be done remotely; even while the production line is still running, and that means shutdowns and stoppages can be avoided.

Parker Hannifin has joined more than 130 companies in the IO-Link community which represents over 3.5 million nodes achieved in the field, number in a fast evolution/acceleration, factors such as the ease of installation, greater control and improved diagnostics capabilities of IO-Link has won the technology a substantial user base. It seems this type of IO technology is a definitive stride towards the ‘smart factory’ of intelligent devices that manufacturers have been eagerly awaiting.

Doing more with less

If you visit any automotive or packaging plant, the ‘elephant in the room’ is usually the big controller cabinet housing the PLCs and contactors. These cabinets take up a lot of valuable floor space, but now it seems that the cabinet is destined to shrink dramatically. Power supplies, PLCs and Ethernet switches are becoming more rugged, going from IP 20 to IP 65 ratings in many instances. With equipment such as safety relays increasingly moving out of the cabinet, we will start to see the PLC moving out to the tool itself.

Ultimately, factories will regain that premium space that was once occupied by the cabinet and IO-Link masters installed so that the cables are also decentralised. Both will see a dramatic decrease in cost.

This stripped-down ‘do more with less’ business model will encourage those customers who still typically hard wire their valve manifolds to make that leap towards industrial networks, because we now have the power to put real-time intelligent diagnostics into valve manifolds. The customer can easily see if a coil has been shorted or if the voltage is sagging. There’s a lot of information that users can get now that they couldn’t before, simply because there is more intelligence in that pneumatic manifold, enabling flexible manufacturing and better safety.

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