In China, “you can’t even bid on a project unless you can check the box that you have redundancy,” says Benson Hougland, Opto 22 vice president, marketing.
It was out of that need that one of the company’s newest products was born. The Opto 22 Snap PAC Redundancy Option Kit (Snap-PAC-ROK), unveiled on March 29, can be used to design an Ethernet-based redundant control system with maximum reliability and distributed intelligence that can instantly recover from failure, the company says.
Using standard Opto 22 S-series Snap PACs, Snap Ethernet I/O and the new PAC Project Professional 9.0 software suite, customers can use the Snap PAC Redundancy Option Kit to configure automation systems with dual PACs that essentially synchronize and run in parallel. In the event that one controller fails or is knocked off line, the other controller will assume command and continue to execute the control program and the processes it runs with no interruption or restart necessary.
When compared to other redundancy approaches on the market, one big advantage of the ROK solution is its price, according to Hougland. While competitive solutions often require expensive, high-end or specialized controllers to achieve redundancy, the ROK works with two standard S-series Snap PACs, priced at around $1,500 each, Hougland says. Communication is over Ethernet using standard Cat 5 cabling. No proprietary communication protocols, interfaces or custom cables are required.
Redundant Opto 22 control systems created with the Snap PAC ROK provide various advantages for users. For instance, the two identically configured controllers (active and back-up) are able to swap roles in the redundancy scheme at any time, offering flexibility and other benefits during system start-up and commissioning. Redundancy advantages also include a significant reduction in the control system’s mean time between failures (MTBF), and thus even greater levels of reliability for process-oriented applications.
Components of the Snap PAC Redundancy Option Kit include:
•   A Redundancy Arbiter—a standalone processor that connects serially to both controllers and monitors and regulates their status and maintains synchronization of the control program during system startup
•   A Redundant Power Switch, which allows power re-starts to controllers in the event of failure and during firmware upgrades.
The PAC Redundancy Manager, a software utility for configuring redundant systems, including IP addresses, program synchronization and firmware matching, is included in PAC Project Professional 9.0. This utility is also used for maintaining and monitoring a functioning system.
Support for redundant controllers is perhaps the most anticipated and powerful new feature found in Opto 22’s PAC Project 9.0 software, the company says. PAC Project 9.0, which was also announced on March 29, is a full set of software applications and utilities that provide control programming, HMI development, OPC connectivity, database integration, communication with Allen-Bradley Logix systems, and support for controller redundancy.
www.opto22.com
