“IO-Link vs SPE” …
In common factory automation applications, IO-Link easily meets most requirements. Smart Factory developments driven by Industry 4.0 are creating new challenges, though. The portfolio of IO-Link devices is also growing, which in turn is expanding potential areas of application. For example, there is indeed demand for transferring IO-Link over greater distances than the 20 m currently specified.
SPE (Single-Pair Ethernet) promises a number of advantages here. This is why the IO-Link Steering Committee has recently created a working group intended to examine the potential and technical feasibility of a published “IO-Link over SPE” concept study. Karim Jamal of Texas Instruments has been named head of the working group. “Our goal isn’t to replace IO-Link, but rather to expand it with a new interface where it makes sense” said Jamal in summarizing the task. “We place great value on existing IO-Link integration standards like IODD and will keep compatibility in the foreground of our technical considerations.”
IO-Link over SPE will retain the protocol and data model of IO-Link and expand it with a physical interface. With SPE and a potential combination with PoDL (Power over Data Lines), terminals – i.e. sensors or actuators – can also be operated on the lower field level with sufficient data bandwidth.
With IO-Link over SPE, IO-Link messages are transferred over a single-pair line – without TCP/IP or UDP – instead of being transferred as pulse-encoded telegrams over the classic 3-lead cable at 24 V. The advantage is that the core components of IO-Link communication, the implementations of the protocol layer and the functions remain unchanged.
In other words, IO-Link is still IO-Link. IO-Link over SPE isn’t another Ethernet-based bus system, but rather a point-to-point connection with no IP addressing. All the defined interfaces and functions are retained. Established IO-Link integration standards like IODD, the OPC UA Companion Standard, JSON mapping and fieldbus integration can still be used in the exact same way.
