A Next Generation Safety System (SIL) to Protect Your People, Assets and the Environment
Nexus OnCore Safety Systems
In today’s competitive production environment, process industries demand control and safety systems that increase productivity, reliability and quality while lowering cost. The Nexus OnCore† Safety System is a next-generation Safety Instrumented System (SIS) that is an advanced, easy to learn, easy to use, fully configurable solution that creates failsafe conditions to protect people and equipment.
The Nexus OnCore Safety System is a programmable electronic safety-related system that complies with IEC 61508 (2010), having a system capability of SC 3 (Systematic Capability) and Safety Integrity Level (SIL) 3 by 2oo3 (2 out of 3) architectural design standards. It can be applied to those applications where customers are wanting to achieve a system rating up to SIL 3. SIL is an indication of the reliability of safety instrumented functions (SIF) or its Probability of Failure on Demand (PFD).
SIL certification is provided by third party experts such as exida, or TüV for electronic hardware which has been shown to meet the reliability requirements of IEC61508. To meet the safety lifecycle requirements of IEC61511, certified hardware must be applied properly, and fully documented by the end user.
There are many safety lifecycle activities (e.g., PHA, HAZOP, SIL targeting and verification, etc.) required to meet the IEC61511 requirements. Each customer site will have unique equipment arrangements, with differing field instruments, and software requirements that cannot be pre-packaged without a high level of customer interaction.
Most products today are being marketed as “SIL capable”. SIL capable is defined as being able to be used in a Safety Instrumented System (SIS) and can be validated and documented after the proper functional safety lifecycle activities have been performed by individuals qualified in Functional Safety.
A SIS is an instrumented system used to implement one or more SIFs. The purpose of a SIS is to prevent an unsafe event from happening or to mitigate the severity of an event by taking proactive action to move the process to a safe condition.
A SIF is a function to be implemented by a SIS, which is intended to achieve or maintain a safe state for the process with respect to a specific hazardous event. Hazardous events are those that could result in loss of life or personnel injury, not just equipment damage.
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The Nexus OnCore Safety System has been certified to be used in SIL 1, SIL 2 and SIL 3 applications. The SIL rating of your individual SIFs will be based on aggregated SIL rating of all instrumentation, logic solvers, and final control elements (e.g., valves) in your SIS – with the least capable having the greatest impact on the overall system level capability. The Nexus OnCore Safety System has the highest reliability rating of the SIF components. The tables below are provided to help you assess the SIL requirements for your project.
Nexus OnCore Control System and Nexus OnCore Safety have been developed by a team of domain experts who have over a century of experience successfully delivering over 11,000 projects using a wide range of control platforms. The Nexus OnCore platform benefited from the collective knowledge of this team, resulting in robust control and safety platforms that take full advantage of best in class features.
Combined with the Nexus OnCore Control System, complete plant control and protection through a common configuration software provide simplified expansion capabilities and reduce overall installation and training costs.
Designed to serve a wide variety of industrial protection applications from Emergency Shutdown Device (ESD), Burner Management Systems (BMS), Emergency Trip Systems (ETS), and Compressor Protection Systems.
Architecture balances high safety with high availability by adopting a 2oo3 architecture with diagnostics throughout the safety loop, including all input modules, controllers and output modules.
- Each type of module is designed with built-in diagnostic functions of high diagnostic coverage (DC) to reduce the undetected failure rate.
- By utilizing low common cause design, the probability of multi-failures can be minimized to effectively reduce spurious trips.
The overall design enhances reliability by using a 2oo3 architecture with diagnostics to ensure loop safety, multiple levels of voting on the data stream, physical independence among triple redundant modules with high DC.
Availability is increased using a dual power supply with branch circuit detection to avoid loss of power and through degraded operation of 3-2-0 mode is permitted.
Enhanced diagnostic capability by delivering channel level diagnostics:
- AI: out of range, open and short circuit detection
- DI: open and short circuit detection
- DO: relay coil current protection
Redundant architecture allows independent replacement of processor and I/O modules without a complete system shutdown.
Integrated HMI software package includes embedded historian and engineering tools.
- Historian can be expanded without additional equipment, saving cost and allowing for more analytical capability
Easily configured software allows for customization of HMI screens, reducing training time while improving the user experience.
Simplified, single license that covers all aspects of your process control and safety system. No additional license fees are required in the future if you choose to add points, cards or expand the capability of the integrated data historian.