IIoT & Energy
A hub that brings positioning systems to the controller over one 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 swapped fieldbus and hardware itself ever since.
The task
A machine with format adjustment carries many small positioning drives, and each of them needs power, data and an address at the controller. So far that meant one cable per drive to the controller, and one variant of the drive per fieldbus.
halstrup-walcher wanted a hub in between: the drives connect to the hub over IO-Link, the hub connects to the controller's fieldbus over a single Ethernet cable. The hub knows the state of all drives, moves them synchronously 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. For the client it was the first product with object-oriented firmware; the base was to be laid out so that its own team takes it over and develops it further.
The solution
The firmware separates three things: the application with hub state machine, synchronous 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 addressed over POWERLINK or EtherCAT. The second fieldbus was added as a module, with conformance test, without touching 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 unites both. Because the hardware layer is encapsulated on semf, our software architecture, the application moved along; what was written anew was the hardware abstraction, checked with integration tests in the CI pipeline before the application ran on it.
The results are the firmware for both generations, the architecture and state machine documentation, the device description for the controller and the system test against a real PLC. On this base, 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 sizes.