Designed Specifically for Paralleling Control Switchgear; Enhances Operation, Reliability and Serviceability of Programmable Logic Controllers

Florham Park, N.J. September 13, 2011 — Emerson Network Power, a business of Emerson (NYSE: EMR) and a global leader in maximizing availability, capacity and efficiency of critical infrastructure, today debuted an ASCO Ethernet redundancy and I/O solution that simplifies efficient operation, reliability and serviceability of quad-redundant programmable logic controllers (PLCs) for paralleling control switchgear.

The ASCO Ethernet redundancy and I/O solution comprises software, PLC and I/O configurations that represent the only quad-redundant control method designed specifically for paralleling control switchgear. It also includes a full set of system diagnostics that signal any failure, not just those that could bring down the system. The information is displayed on the master PLC, I/O communication status screen and displayed and logged on the ASCO PowerQuest® Power Monitoring and Control System.

Developing solutions dedicated to power switching and controls duty is part of a century-long tradition of ASCO product research and design that has produced many industry “firsts,” including the first microprocessor controller for automatic power transfer switches. This ASCO solution marks an important step forward in managing hot standby and ‘bumpless’ quad-redundant PLC control of paralleling control switchgear, especially during a possible PLC failure.

The software, PLC and I/O configurations combine to reduce system cost, extend life, and simplify PLC startup, operation and servicing when integrated into power switching and controls equipment. The ASCO solution’s Ethernet redundancy employs a simple Ethernet network that can be copper or fiber based and does not require fiber optic rings and hubs—savings can exceed $100,000 for sophisticated multi-genset emergency power systems with a lineup of paralleling control switchgear sections.

Ethernet’s robustness and reliability, and low power, small PLCs that run cool and require minimal space help extend system life. PLC startup is truly automatic, especially after a failed PLC has been replaced, or the emergency power system has been ‘blackout’ tested. The entire solution can re-join the network at once, without having to follow strict rules governing sequential startup. Straightforward system design makes possible ‘fix it ‘n go’ servicing. Master PLCs are hot swappable, for example. For increased redundancy, the ASCO solution also supports the option of redundant I/O

Reliable Operation
The ASCO solution supports up to four master PLCs and up to 50 smart Ethernet interface units. Emerson Network Power configures the smart Ethernet units so they can ‘listen’ to up to four master PLCs simultaneously, but it also can be the control method of choice for dual master PLC redundancy as well. All PLCs ‘talk’ to each other and operate 24/7, constantly updating and synchronizing data and processes. One PLC is ‘in charge,’ with the others in hot standby. In a quad-redundant solution, the I/O prefers to listen to PLC1 first, then PLC 2, then 3 and finally 4.

If PLC1 fails, the I/O will seek the next available PLC in order and stay on that PLC unless it fails. If it does, the I/O will first seek PLC1, then the others in order. Switching from one PLC to another is bumpless, that is, the quad-redundant design operates at a faster speed than the power switching and controls processes it monitors. Switching will not adversely affect paralleling control switchgear operation.

As with all ASCO solutions, the ASCO Ethernet redundancy and I/O solution was thoroughly field proven before its market debut. It now is operating in a number of large, power switching and controls installations in North America and the Middle East.

For more information on the ASCO Ethernet redundancy and I/O solution visit www.EmersonNetworkPower.com/ASCO.