Functional Safety Implementation in Industrial Equipment

September 02, 2015 by Jeff Shepard

Renesas Electronics has expanded its industrial support with the launch of its RX111 Safety Package, to significantly reduce development time to implement functional safety for industrial equipment and devices, such as sensors, safety controllers, and industrial drives. Industry 4.0 and the Industrial Internet of Things (IIoT) movements are driving the need for more robust and inherently safe devices on the factory floor, from the PLCs down to the sensors at the edge of the factory network. The European Machinery Directive also requires that equipment provides support for functional safety.

Renesas has built upon its knowledge and experience related to functional safety within the automotive field, and leveraged its expertise in the design and development of microcontrollers (MCUs), to offer developers a broader range of functional safety solutions that help expand the adoption of functional safety in the industrial field.

The new RX111 Safety Package solution supports the power-efficient RX111 MCUs ideal for sensor-based applications, for which demand is growing rapidly as the importance of monitoring the state of industrial systems increases. Certified under the IEC 61508 SIL3 international functional safety standard, and meeting a strict third-party certification for MCUs, the RX111 Safety Package is one the industry’s most comprehensive MCU safety packages.

It includes an exhaustive self-diagnostic software library set that reaches diagnostic coverage representing more than 100,000 combinations to cover both random and systematic faults to support both SIL2 and SIL3 applications. In addition, the Safety Manual includes vital information such as FIT rates that can be passed on to a certifying body to reduce complexity in conformance. The solution significantly reduces the development time related to diagnostics performed on the MCU, by providing the safety analysis and study of failure diagnostic methods and diagnostic yields.

The RX111 Safety Package extends Renesas’ commitment to functional safety support and enables seamless compliance with functional safety requirements in a variety of applications, complementing the RX631, RX63N Safety Package introduced in August 2014 for industrial equipment applications requiring high-speed data processing, such as motion monitoring or network communication.

Features of the RX111 Safety Package: 1) Diagnostic program for compact, power-efficient MCUs, suitable for use in sensor devices; The self-diagnostic software uses fault simulation (Note 2) to obtain a clear basis for diagnostic yields and contributes to more efficient development. To accommodate the comparatively smaller ROM capacity of the RX111 MCUs, Renesas has also reduced the self-diagnostic software to half the size of earlier versions for the RX631 and RX63N, further boosting the high cost-to-performance ratio associated with the RX111 devices. It is also possible to select a product version with smaller memory capacity to further boost performance relative to cost. This makes it easier to switch to electronic equivalents of mechanical safety mechanisms in applications such as state monitoring sensor devices, motor drive devices for torque cutoff control, safety relays, and safety switches.

2) IEC 61508 SIL3-certified for efficient safety development; The provided safety package includes a safety manual comprising a safety analysis of each of the MCU’s internal functional blocks. The software itself is performing self-diagnostics on the CPU, RAM and flash ROM. Fault simulation evaluation (Note 2) verifies the fault diagnostic rate of the CPU. This provides a precise basis for reporting the diagnostic rate. The complete safety package including the self-diagnostic software is IEC 61508 SIL3 certified by TÜV Rheinland Industrie Service GmbH of Germany, an internationally recognized third-party certification authority. Using this software eliminates the need to obtain separate qualification of the software development process conformance as required under the IEC 61508 standard. Customers utilizing the RX111 Safety Package can reduce the development period devoted to MCU safety analysis by approximately one-third.

3) The RX111 Safety Package Evaluation Kit for easy evaluation; The RX111 Safety Package Evaluation Kit bundles an evaluation board with a built-in RX111 MCU and self-diagnostic software, enabling system designers to get started immediately with diagnostic software performance evaluation and initial system consideration. The evaluation kit includes an evaluation version of the certified IAR Embedded Workbench for RX, Functional Safety Version (from IAR Systems) which has also been used for initial system assessment.