Opto 22 introduces SNAP PAC redundancy option kit

Hardware and software let users build redundant PAC systems easily.

By Renee Robbins April 1, 2010

Opto 22, developer the SNAP PAC family of programmable automation controllers, I/O, and accessories, has released the SNAP PAC Redundancy Option Kit (SNAP-PAC-ROK), which enables users to design an Ethernet-based redundant control system with maximum reliability and distributed intelligence.

Using standard Opto 22 S-series SNAP PACs, SNAP Ethernet I/O, and the newly announced PAC Project Professional 9.0 software suite, users can configure automation systems with dual programmable automation controllers (PACs) that essentially synchronize and run in parallel. In the event one controller fails or is knocked offline, the other controller will assume command and continue to execute the control program and the processes it runs, with no interruption or restart necessary.

This feature, known as "redundancy," provides many advantages. Foremost among these is a significant reduction in the control system’s mean time between failures (MTBF), and thus even greater levels of reliability for process-oriented applications in the manufacturing of semiconductors, thin film LCD, and other high-value product batches. Redundant control systems also prove advantageous (and are frequently mandated) for processing, handling, and transport of chemicals, pharmaceuticals, and oil and gas products and byproducts.

IC Engineering Project Manager Ryan McCollum has implemented large-scale automation projects at the research and testing facilities of one of the world’s largest oil companies. He says, "Redundancy, combined with the larger memory and better multi-tasking capabilities of the Opto 22 PACs, make them superior to most PLCs. The Opto 22 hardware also provides a variety of other useful, often exclusive capabilities."

Redundant Opto 22 control systems created with the SNAP PAC Redundancy Option Kit provide several unique features, according to the company. For instance, the two identically configured controllers (active and backup) are able to swap roles in the redundancy scheme at any time, allowing flexibility during system start-up and commissioning.

The kit includes the SNAP PAC Redundancy Arbiter, which is a standalone processor that connects serially to both controllers. It and monitors and regulates their status, and maintains synchronization of the control program during system startup. The kit also includes the SNAP redundant power switch, which allows power re-starts to controllers in the event of failure and during firmware upgrades.

With redundant Opto 22 controllers , customers also can keep their control system online and operating even as they make changes to, or completely replace their control program. Once the new program is downloaded to one controller, it becomes active and the second controller is updated with the new instruction set. Customers can repeat this process as often as they like, as they test, fine tune, and configure their control program to their exact specifications. Similarly, customers seeking to make their existing system redundant need only to add the SNAP PAC Redundancy Option Kit, the latest version of PAC Project Professional, and a second S-series controller, which, upon commissioning, is automatically populated with the most current firmware and control program.

Other ways in which an Opto 22 redundant system differs from those of other automation suppliers: It uses the company’s standard controllers, and it communicates over Ethernet using standard Cat 5 cabling. (No proprietary communication protocols, interfaces, or custom cables are required.)
See also: Opto 22 introduces PAC Project 9 control programming software suite

– Edited by Renee Robbins, senior editor
Control Engineering News Desk

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