The basic concept of functional safety has been in place for a long time. It operates on the principle of protecting users from harm or injury during use of equipment or machinery. The scope of functional safety is wide and varied in industrial operations, domestic applications, autonomous transportation, and other related activities where machinery/devices are either operated individually or collectively. Electro-mechanical appliances such as household equipment, autonomous vehicles, air conditioning systems, gas heating boilers, fire monitoring systems, and other industrial systems (conveyors, etc.) all have aspects of their operation that could create potential hazards which could subsequently result in some sort of an injury or harm. The same can be said for electronically controlled and electro-mechanically operated functions in semi or fully automated solutions. Overall, functional safety is a measure of the confidence that a machine or system will immediately implement safety and operator protection measures when needed.
IEC 61508 provides proper insight into the functional safety standard for electrical, electronic, and electro-mechanical equipment. It has specific principles for the application of similar equipment for sector-specific use cases. Functional safety standards exist to provide the necessary regulations and compliance testing requirements for a wide variety of different equipment. Human operators and users are always protected from hazards associated with potential failure, unexpected equipment behavior, or equipment misuse.
With the increasing emphasis on industrial operational effectiveness improvement through initiatives such as Industry 4.0, smart factories, and the Industrial Internet of Things (IIoT), automated systems and machinery form a significant part of any industrial manufacturing process. Although these components have provided enough space for management in improving process optimization by reducing the cost involved, they have significantly increased the chances of failure at the unexpected level of operation throughout the process. Particularly, the automation is primarily led by the embedded solutions along with support software platforms, the chances of device-level malfunction can shut down or cut off the entire system or even conceivably the plant operation. In this case, following the functional safety measures not only safeguards workers from equipment hazards by using a formal and comprehensive approach by identifying and analyzing dangerous conditions that may occur and the consequences for operator safety, but it also reduces operation downtime.
Functional safety incorporates two fundamental concepts: safety functions and safety integrity levels. Within a safety function, all the parts, including the sensors, control system, and actuators, are collectively examined to determine the probability and frequency of failure. Whereas safety integrity levels define the degree of risk reduction required to reduce the risks involved to an acceptable level. A safety function involves any action or operation required to ensure the safe running of the equipment. This function typically involves some form of sensor/actuators, a control circuit, some electromechanical devices such as motors, etc., and a mechanism to maintain safety integrity. The unwanted events involved with these devices/systems can pose a serious threat. The actions performed at that instance define the primary safety function. However, the timing between these interrelated actions is crucial, particularly if separate controllers are used for the sensing and the control actions.
For the almost a decade, Renesas electronics has been an active member of several functional safety working groups and has strongly contributed to relevant functional safety standards. Renesas offers a one-stop functional safety solution with its composite wide range of MCUs and related software framework. The TUV certified software kit offered by Renesas has reduced the time for constructing functional safety systems and the certification process on MCUs, irrespective of their domain-specific application.
Renesas MCUs, together with various sensors; from MEMS accelerometers, environmental sensors, to several visualisation devices, make up primary components of a control system. The internal HW features of latest microcontrollers combined with necessary SW dramatically helps simplify the development process to achieve functional safety compliance. The certified software and reference solution for most of Renesas MCUs, RA and RX family of devices, have been designed to comply with IEC 61508 and include a certificate and safety manual. These software modules are certified under IEC61508 parts 1 to 7, as well as Part 3 of IEC 61508 which stipulates the use of formal software design architectures, validation, and testing as a core part of implementing functional safety.
With the increasing deployment of industrial automation machinery that operates alongside human co-workers, the need for functional safety is paramount and high computing SOCs along with the state-of-the-art computational techniques have shown a solid way to sort out the related issue. Adherence to the functional safety standards highlighted in this article is a critical success factor for industrial equipment manufacturers.
Adding Intelligence to Functional Safety:
The current evolution of machine learning/AI and higher performance computing hardware is driving highly efficient safety solutions - whether it’s preventing systematic failures or anticipating and mitigating future risk, integration of various artificial intelligence models also a key consideration for the engineers when designing functional safety systems.
The flow diagram shown provides a brief overview of a possible industrial use case to achieve intelligent functional safety. During operation, identification of the fault at the right time with the right location and providing the right cause for the same plays a significant role. The artificial intelligence/machine-learned system delivers a good scope of coping with the above issue. Artificial intelligence enables and increases machine capabilities and makes the process sustainable for unfavourable circumstances. Here a field system associated with Renesas MCUs has state-of-the-art solutions for data collection and computational space for AI/ML algorithms framework to foreseeing and detecting abnormal states and anomalies. The complete set of solutions starting from embedded to dedicated software architecture has the facility to provide alerts for asset/operation status and recommend the corrective actions for the same. This will ultimately improve safety and reduce the respective downtime and related cost involved.
Industries are keen to make the process automated to avoid any possible system failure and related mishaps which usually lead to plant shut down or injury to operators. Therefore, incorporation of relevant machine learning models at the device level will enable the system/operator to take corrective measures in real time. In turn making the Functional Safety design processes offering the pathway to higher reliability, diagnostics, resilience, and redundancy.