At the request of a customer, E-T-A decided in 2019 to develop a low-cost bus controller for the REX12D series of electrical circuit breakers. Among other things, the controller is designed for machine control systems in automated environments, specifically for a lathe with multiple sensors and drives. The fieldbus connection is used for continuous data transmission of all status information and measured values of the safety system. Thanks to reliable overload and short-circuit detection, it protects against the consequences of unwanted anomalies and system downtimes.

E-T-A consulted Leber for the design and development of the fieldbus connection. The service provider from Schwaig near Nuremberg has experience in integrating communication functions into a wide range of systems and products. Leber's task was to generate multiprotocol-capable hardware including circuit diagram, BOM, layout, EMC and ESD test. This involved implementing and certifying the protocol stacks relevant to E-T-A for Profinet, Modbus, EtherCAT and Ethernet/IP.

The result of the cooperation was the ControlPlex System CPC12, which creates transparency across all levels of the automation pyramid on the basis of Hilscher's netX-90 communication controller. Three key factors contributed to the decision in favor of Hilscher technology: development speed, form factor and pricing.

Maximum development speed

For E-T-A, the CPC12 is the first product with integrated technology from Hilscher. Andreas Funcke, project manager in the Automation & Process Control product division at E-T-A, brought in external expertise for the development. "Our aim was to develop a cost-effective bus controller for electronic fuses," explains Funcke. "To achieve this, we naturally wanted to keep the development time as short as possible. So we brought Leber on board, who already have many years of experience with Hilscher's netX SoCs."

Leber has been an official NetX design-in partner since the end of 2018. "From the start of the project in February 2019, we developed a functional prototype in just under six months," says Jörg Klenke, Managing Director at Leber, outlining the course of the project. "After another six months, the market launch of the bus controller began. Despite the onset of the coronavirus pandemic, we were able to develop a product ready for series production in a very short time."

Separate cores

E-T-A relied on the netX-90 SoCs fieldbus controller when developing the CPC12. It is the smallest multiprotocol-capable chip on the market. "The distinguishing feature for us was that the netX 90 is a dual-core fieldbus controller," recalls Wilhelm Adacker, Embedded Systems Software Architect at Leber. "This innovation made it easy to resolve many timing conflicts that we had encountered in previous netX projects."

Unlike the netX 51 or netX 52, two Hilscher communication controllers of a previous generation, the netX 90 no longer shares a core between the customer application and network communication. Instead, a 100 MHz ARM Cortex-M4 is available for both tasks. This solves problems such as priority distribution, complications with high network loads or shifted task interactions.