IIoT & Energy
A hub that connects positioning systems to the controller over a single Ethernet cable
For halstrup-walcher we developed the firmware of the PSxHub, an IO-Link hub that bundles positioning drives and connects them to the machine controller over real-time Ethernet. The software is built so that the client has since changed the fieldbus and the hardware on its own.
The task
A machine with format adjustment has many small positioning drives, and each of them needs power, data and an address at the controller. Until now, that meant one cable per drive to the controller, and one drive variant per fieldbus.
halstrup-walcher wanted a hub in between: the drives connect to the hub over IO-Link, and the hub connects to the controller's fieldbus over a single Ethernet cable. The hub knows the state of all drives, moves them in sync and reports to the controller what it needs to know. And because machine builders use different fieldbuses, changing the fieldbus was to be a matter of firmware, not hardware. It was the client's first product with object-oriented firmware; the base was to be designed so that the client's own team could take it over and develop it further.
The solution
The firmware separates three things: the application, with the hub state machine, synchronised motion and drive management; the communication with the controller through the fieldbus stack; and the hardware underneath. Between application and fieldbus sits a mapping of services and objects, so the application does not know whether it is being addressed over POWERLINK or EtherCAT. This is how the second fieldbus was added as a module, including conformance testing, without any change to the drive logic.
The same principle carried the port: the first generation ran on a microcontroller with a separate network chip, the second on a multiprotocol SoC that combines both. Because the hardware layer is encapsulated on semf, our software architecture, the application moved across with it. What we rewrote was the hardware abstraction, tested with integration tests in the CI pipeline before the application ran on it.
The results are the firmware for both generations, the description of the architecture and the state machine, the device description for the controller, and the system test against a real PLC. On this basis, halstrup-walcher took over the transfer to series production and further development in-house; today the PSxHub is on the market with additional fieldbuses and in several configurations.