Building a flexible, functionally safe control system architecture

With the ESX.3ios from STW, the control system – e.g. of a mobile machine – can be expanded with additional inputs or outputs. In order to simplify the design of a functionally safe system architecture, and provide more flexibility in that design, STW has recently had the ESX.3ios certified by the TÜV. These slave I/O modules have been certified according to EN ISO 13849 (up to Performance Level PL d) and EN 61508 (Safety Integrity Level SIL 2). In combination with a safety certified master controller, decentralized, functionally safe control architectures can be implemented. The ESX.3ios I/O module transfers the signals of safety sensors and actuators to the main controller, for example STW’s ESX.3XL, using a functionally safe method. There is no need for additional SIL2/PL d control units in this example system.

The ESX.3ios has 16 inputs and 15 outputs and is designed for harsh environmental conditions, such as those encountered in mining, construction or agriculture. The ESX.3ios has a protection rating of up to IP6k9k and a specified operating temperature of -40°C to +85°C. The communication protocols CANopen and CANopen Safety are currently supported, and support for J1939 and STW’s own ECeS protocol is planned in the near future. The ECeS protocol significantly reduces the bus load compared to the generic CANopen Safety protocol. A wake-up functionality can be implemented on CAN 1.

The programming and implementation of new applications has also been simplified with the introduction of the safety-certified ESX.3ios. Thanks to support within STW’s open-source development and life-cycle management tool, openSYDE, the I/O modules can be configured and updated in a functionally safe manner. With the STW modular control system and the openSYDE software suite, the designers of mobile machine control systems have the tools at their disposal to build a control system in a flexible, intuitive and safe way.