Past Reliability Enables Future Flexibility

GE's MarkVIeS Fault-Tolerant Safety Controller Is Triple-Modular-Redundant and exida-Certified for SIL 3 Applications

By ControlGlobal.com Staff

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There's no substitute for experience, especially in generating new innovations. For example, General Electric Co. has been in the controller business for decades. It started making its Mark series high-availability controllers in the 1960s for industries requiring extreme reliability and availability, and since the 1980s, its triple-modular-redundant (TMR) controllers have helped maximize process and plant uptime in more than 10,000 critical applications. However, while Mark controllers have been widely deployed, they were typically used only by GE's internal customers. Even the most recent family members, MarkVIe intelligent controller and MarkVIeS intelligent safety controller, were only released internally in 2005.

Fortunately, the consolidation of GE Intelligent Platforms with GE's Controls Center of Excellence for power and water about six to eight months ago is allowing the converged organization to release a newly updated version of its Mark VIeS control system.

"We looked at all of GE's businesses, and industrial controls are needed at all levels, but now we're making the controls experience consistent for all of them," says Rebecca Boll, product line leader for Intelligent Platforms' control and communications systems. "This is also part of GE's effort to invest in the Industrial Internet and make it as easy to use as the regular Internet is for mainstream consumers."

As a result, MarkVIeS consists of a main control processor, Ethernet drivers for communicating with its I/O and control networks, and simplex-, dual- or TMR-configurable I/O modules. Its control logic is programmed in a combination of function block diagrams (FBDs), relay ladder diagram (RLD) and sequential function charts (SFCs), which are executed by a real-time operating system (RTOS). Its I/O network is a dedicated, full-duplex, point-to-point protocol, and it supports deterministic, 100-Mbps communications suitable for local or distributed I/O modules.

"This I/O architecture provides the extreme flexibility needed to meet very specific requirements and allows users to apply and optimize them quickly," says Ashok Acharya, product manager for GE's Mark safety controllers. "Safety systems typically have multiple loops, but not all of them need extreme redundancy. MarkVIeS allows users to customize each loop with the right safety integrity levels (SILs) and modify them easily if needed."

To serve many of the same mission-critical applications as its predecessors, Mark VIeS is exida-certified for SIL 3 applications in compliance with the IEC 61508 standard, and implements redundancy for safety based on its SIL requirements. It also holds an Achilles Level I cybersecurity certification from Wurldtech.

While much of its hardware remains the same, MarkVIeS's software and networking capabilities have been streamlined. For example, a couple of years ago, it added the OPC UA networking protocol for communicating between its Control ST-based Workstation software and PLCs and DCSs. Also, last year, it integrated a shared I/O communications concept between its safety and non-safety controllers using GE's Ethernet Global Data (EGD) protocol.

In addition, MarkVIeS's Workstation software toolset employs several other sections of GE's ControlST software, including ToolboxST for initial configuration and maintenance; Trender, with several forms of data collection to perform time-based signal plotting; and Alarm View to display and manage live and historical alarm and event information in accordance with the ISA 18.2 standard.

Also, because simulation of processes and associated control can be essential for training and validation, the controller has Virtual MarkVIeS, which provides a PC-based form of itself. It supports execution of application programs, communication interfaces with ToolboxST, EGD services, and process alarm management. "This allows users to test and examine different data without having to connect to a physical system," explains Acharya.

Finally, MarkVIeS uses exida's exSILentia software to help analyze safety instrumented functions (SIFs), verify that it's meeting safety requirements and demonstrate compliance. "Users can employ this tool to calculate the SIL functions they require, and decide on the architecture and SIL level they'll need to achieve for specific applications," adds Acharya.

For more information, contact GE Intelligent Platforms at 800-433-2682 or visit www.ge-ip.com.

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