Reliable and Stable Process Control System
The HOLLiAS MACS DCS control system is developed with excellent cost-effectiveness in mind, possessing attributes such as the most advanced software and hardware, reliability, versatility, openness, and stability. All of the system’s core components adopt a unique “redundancy and failure-tolerance”controller structure, where the system’s usability performance is 99.999%.
The HOLLiAS MACS of HollySys adequately satisfies the process control, inspection, optimisation, and management requirements for production using petrochemical equipment. The system has a framework that is open, flexible to configure, and scalable. It has an open network technology that can integrate with the HSIE (HollySys Industrial Ethernet) and field bus technology, ensuring consistency in configuration data pertaining to the respective process-object, data transmission transparency, and object reference consistency. It satisfies the automation requirements for the whole petrochemical plant, and achieves the sharing of petrochemical automation data resources.
HollySys developed its own industrial Ethernet that has a national patent: With improvement in Ethernet protocols to achieve a highly reliable and definite industrial real-time communication network, and adopting a series of advanced technologies such as protocol technology based on priority levels and smoothing technology based on adjustable flow.
The system’s components have been developed with completely reliable redundancy design technology in mind, with the host controller using standby dual redundancy configuration, designed with hardware redundancy switching and failure self-test circuit. A hot backup was done for the two host controllers, using a standby operation synchronisation mode to realise bump-less switching.
Power supply redundancy: The power supply modules are specially designed, powerful and stable, and are configured for redundancy. Many power sources are used in parallel and operating with equalised flow. If one of them breaks down, another one will bear all the load immediately.
I/O equipment redundancy: All IO acquisition modules can be configured for redundancy, fully satisfying the special traits and requirements for the petrochemical industry.
Network redundancy: The master control unit is configured with dual redundancy industrial Ethernet connection to realise system network redundancy. It has a built-in Profibus-DP master interface, where all I/O modules direct support redundancy DP bus.
HollySys is equipped with an EMC laboratory which can perform all EMC tests on every board that was designed and prepared, and all environment tests (such as temperature and humidity tests, high and low temperature transient tests, corrosion tests) can be completed on boards prior to release from the plant. This will ensure that the product has excellent electromagnetic compatibility.
All of HollySys’ control system components (including controllers, I/O cards, bases, and power sources) contain anti-environmental-corrosion properties, and operate in the long-term in a G3 environment in accordance with the ANSI/ISA S71.04 standards.
The project was a resounding success with high client satisfaction. Out of over 200 suppliers, HollySys was rated as one of their “Top 10 Suppliers” for their project.
Key factors leading to the project’s success:
The project adequately takes into account characteristics of usage in the China’s petrochemical industry, where goal-oriented graphics design and programming technology adopted for software used to generate and display process simulation flowcharts, including functions such as graphic object editing, the combination and decomposition of graphic objects, and the defining of dynamic characteristics of graphic objects and human-machine interactivity to actively manage the graphic object library. Such an object-oriented graphical user interface design technology can create complicated and beautiful graphical user interfaces, and support animation and graphical zoom functions.
Connecting with field equipment using foundation fieldbus or HART, HollySys asset management system (HoLLiAS AMS) significantly raised the equipment’s maintainability, helping clients to realise the preventive maintenance of equipment, reducing maintenance costs, ensuring the safety, reliability, and long-term no-breakdown operations of petrochemical plant equipment. Maintenance personnel can now make use of authorised user privileges at any time and any place to monitor the whole plant’s equipment usage status, and be updated about the field equipment’s diagnostic status.
In the midst of DCS control operations, with the inclusion of foundation fieldbus technology and HART compatibility, self-diagnostic results of field equipment can be accurately reflected.
At the same time, the system is able to use the data definitions and diagnostic data of multiple equipment to provide higher-level process-oriented diagnosis, such as clogged impulse lines of instrument, instrument air pipeline failure, and ambient temperature status diagnosis.
HollySys’technology allows online control of production, and allows the operator to closely monitor and manage the different key factors of plant management (cost, quality, and planning). At the same time, it is able to facilitate timely monitoring of production process feedback statuses, timely adjustments, and coordinate the company’s different resources to ensure that production operations are at their most optimised level.