Are Wireless Interfaces The Future For Machine Control?

Paul Rowlett, product manager for process drives at Control Techniques, gives his view on possible ways the automation industry will adopt wireless keypads.

In November last year, I visited the SPS IPC drives trade show. The event is Europe’s largest showcase for industrial automation technology, and visiting the stands of various exhibitors can shed interesting light on future trends.

My trip to SPS made me wonder about the long term future of keypads on variable speed drives and other automation components. A physical keypad is limited because it has a set number of buttons that cannot change, and because you do not want it to cost too much.

There has been a trend over the last few years for drives to enable configuration and parameter adjustment via web pages or apps running on smart devices like tablets and phones. So, what if the keypad was not physical at all?

The benefits of wireless interfaces

Technologically, there is no reason that a drive with an entirely wireless interface could not be created today. A wireless ‘keypad’ would simply be an app or website accessed via a smart device. This would allow for a rich and flexible interface, utilising the high resolution, full colour displays typically available on these devices. Such a display could be used to analyse all available data, and to produce engaging charts or other graphical representations to instantly see what was going on with a particular drive.

A wireless keypad would allow full customisation of the drive’s interface. Interfaces could be customised according to industry, so that there was one interface for customers operating pumps, another for customers in the port cranes industry, and so on. An operator in the water industry, for example, would find that the interface was set up to talk in a way he could instantly understand and the drive manufacturer would ensure this was translated into the parameters of the drive – making it fast and convenient for the customer to set up and operate the drive. One can even envisage developing bespoke interfaces for individual large customers.

The limitations of wireless keypads

The hardware required on the drive to communicate with the software or app is easily integrated into components already in the drive, such as printed circuit boards. Meanwhile, the operator is likely to use an existing smart device. For these reasons, it might seem logical to assume that doing away with keypads may result in a small cost saving.

There are several technologies that could be employed to provide the graphical user interface (GUI), both in terms of communications and also the user interface. Each technology path has considerable advantages and disadvantages.

To provide the graphical user interface (GUI) there are two key technologies that come to mind; mobile apps and web pages.

Let’s consider web pages first. The key benefits here are that there is no need to install and manage software on a device other than to have a web browser, and there is no chance of incompatibility with drive firmware versions because the user interface is actually provided by the drive firmware.

As interest around Industrial Ethernet continues to grow, replacing traditional Fieldbus, Ethernet interfaces on-board drives are becoming more common and also more sophisticated. Many of these interfaces already provide web pages that allow the user to manage the drive configuration. These web interfaces are popular with customers and have the potential to replace traditional PC based software programs that are used to manage the drive configuration. The step to replace keypads using mobile devices is likely just a small step further along this path.

The language that is used to render web pages, HTML,  is well defined, device agnostic and has already proved to be extremely robust in terms of forwards compatibility with web browsers. It is highly likely that pages created today will be supported on new computing platforms for many years. In contrast, in 10 or 20 years will we still be using PCs? If we are, will the drive supplier’s software still be compatible with the latest version of Windows?

The major downside of webpages is that they do add cost to the drive in terms of computing power and memory. This challenge is most acute with the lowest priced, smallest and most simple drives.

The alternative is to create mobile apps. This has the benefit that it moves the need for computing power and memory from the drive, onto the mobile device which generally has both in abundance. This also allows the developers to be far more creative because the environment in which the app is running is well defined, such as screen sizes and resolution. They also usually offer access to other information, features and functions of the device such as geo-location, vibration, cameras and sound. In addition, unlike web-based interfaces, new app updates can deliver new functionalities or fix problems that have been discovered in the field.

The key downside of the app approach is that separate apps needs to be created for each device platform that is supported, for example, iOS, Android and Microsoft. And, as with PC based software tools that we use today, firmware compatibility and long term support needs to be carefully managed.

Cloud management

There is a major opportunity for the mobile device to provide a direct interface between the drive and cloud based services in line with IIoT and Industry 4.0. We already see potential in the ability to obtain new drive firmware from the cloud or save drive parameters to the cloud. This would allow the user to securely store the latest drive set-up and even track changes over time. It could also allow the drive manufacturer to better serve the customers; if a breakdown was to occur, the replacement drive could be provided with the latest parameter set stored, installed and ready to run. It also allows the manufacturer to better optimise its products, such as prioritising access to the parameters used most often.

In terms of communications, this can be considered independently of the GUI, and devices could support multiple communication methods. The three key options available for communications are Bluetooth, Near Field Communication (NFC) and Ethernet. Let’s consider Bluetooth first…

Most people are aware of, and familiar with, Bluetooth technologies. It’s supported widely by mobile devices, and could be employed to create the link with the drive. The Bluetooth interface would need to be provided through an option so that the user can pair with the option, rather than having to pair individually with each and every drive. Therefore the option would need to be added and removed while the drive is powered up so not to inconvenience the user.

Another option is Near Field Communication. This protocol provides a communication link to two devices when they are placed in close proximity, usually within 4cm. The best known use of this technology is the payment service, Apple Pay. It is becoming well supported with mobile devices. The advantage of this technology is that there would be no need to pair the devices, however, 4cm is a limitation and with many drives in close proximity, how could you be 100% sure you were communicating with the right drive?

A further option is WiFi. This may be a great option when many drives are connected together through an industrial Ethernet network, allowing the user to browse the network and manage multiple drives, however, careful management of cyber security needs to be taken into consideration.

The advantages of physical keypads

Despite their limitations, physical keypads have some strong benefits. In particular, keypads have the obvious advantage that you only need fingers to use them, so they can still be used if wireless connections go down.

Generally, I look to the consumer world for examples of cutting edge technologies leading the way, and the first devices I can think of that had completely soft interfaces were routers and modems: things that are already connected into your network. With most consumer devices, however, you still do not see exclusively soft interfaces. You do not see, for example, domestic ovens controlled only via app. People prefer to use more traditional interfaces.

Does that mean the keypad is here to stay? Or does the industrial world have a different dynamic that means people will accept 100% soft interfaces?

Which way will things go?

 A key driver of wireless keypads or the use of smart mobile devices could be safety, in the USA new legislation has been introduced that gives tighter control of personnel to access control panels. Here, a mobile device could be an ideal solution.

In general, factories are moving online and towards computerised interfaces. Drive keypads are certain to be part of that trend to some degree.

But I think the trend might be industry or application specific. I can envisage that drives in the food and beverage industry, for example, would benefit from wireless keypads because keypads have crevices which are bad for hygiene reasons. Removing the keypads would optimise them for wash down.

For many industries, the benefit has got to be the way you can customise the interface to the customer. One can imagine specially designed crane keypads, or pump keypads, or keypads for packaging machines.

Remote working is another core trend for the automation industry, and online interfaces are key for this. Remote working allows firms to reduce their labour force and access a much wider talent pool.

Yet I do not believe that wireless keypads will spell the end of keypads on drives, at least not for a very long time. Keypads are a good fallback. Redundancy is the reason. Even if they have a secure wireless interface, many customers will want to know that they can physically interact with the drive in the event that the online interface goes down. It will be like television controls. These days, even in the era of remote or smart phone controlled TVs, most still have buttons. Compared to the past they are smaller, more discrete, and located around the back of the set, but they are still there. I expect this to be the trend for drives: keypads will become smaller, less used, and lower cost, but in some form they will still be there.