A world of true open connectivity
We live in an age of entrenched connectivity. We have the internet, Wi-Fi and the almost universal uptake of communication systems like Ethernet networking.
Yet one of the most common complaints from the manufacturing industry has been the lack of connectivity on the factory floor. The absence of interoperability between devices has made data gathering and sharing much harder than it needed to be and created much unnecessary frustration.
However, the reason devices from different vendors can’t talk to each other or the internet isn’t due to the communication systems being used; it’s the lack of a commonly accepted protocol and methodology suitable for industrial applications.
Industry has however been driving for change and the first credible solution came in 1996, when a consortium of automation vendors partnered with Microsoft to create the OPC DA standard (now often called OPC Classic). OPC isn’t just a protocol; it’s a collection of interfaces, objects and methods that are designed specifically for the automation industry.
Many hardware vendors came on board and produced dedicated server programs that connected to their devices and presented OPC-formatted data for clients to use. Client uptake was strong in certain market sectors — namely HMI and SCADA, where suppliers had previously fashioned a custom driver for each unique device. OPC greatly reduced this burden.
The OPC Foundation was later formed as a vendor-neutral organisation, to promote and develop the OPC standard. Amendments were made but, as technology advanced, numerous limitations became apparent.
Recognising needs were changing, the OPC Foundation produced the OPC UA (Unified Architecture) standard in 2008 (IEC 62541). While remaining completely backward compatible to OPC DA, this revision ensured full platform independence, meaning virtually any hardware or operating system could use OPC UA. X.509 authentication, security and encryption methods are also embedded.
As expected, OPC UA has been widely accepted in the decade since its release, particularly with the industry’s uptake of cloud-based IIoT services. However, its usage has still been somewhat hampered and part of the reason is the relative difficulty in implementing OPC UA. Few devices had supported it natively, meaning users were forced into dedicated gateways (usually just programs running on Windows-based PCs) which only collate data from the factory floor and serve it to OPC UA clients. This extra complexity brought added costs, reduced response times and increased maintenance.
Nonetheless, this barrier is progressively being removed by devices themselves serving OPC UA data and providing direct connections to OPC UA clients. This applies mostly to automation controllers; not only are these widely connected on the factory floor, but their control capabilities make them silos of information. Direct connections are more efficient and simplify networks, as well as reducing both costs and maintenance.
Of course OPC UA isn’t restricted to just controllers — it can be implemented in any device. I’m quite certain a day will come when virtually every device will be OPC UA enabled, without gateways.
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