Mitsubishi Electric has added a high-availability, redundant controller to its Q series programmable automation controller (PAC) platform. The QnPRH succeeds the Q4AR system, and offers a new level of redundancy for system-critical applications. It is based on dual CPUs, power supplies and bases, and combines 'out of the box' system building using standard components. The unit is customised by simple parameter setting - a process that is no more complicated than configuring a smaller PLC.
According to Jeremy Shinton, Mitsubishi's Q Series product manager, the QnPRH is not only easy to install, but is physically 25% the size of the Q4AR, reducing space requirements significantly. It is also fully compatible with other Qn series hardware platforms. Components are hot swappable, so can be unplugged and replaced without having to shut down the entire system, thus avoiding any disruption to system availability. There are facilities for troubleshooting, historical data logging, trend analysis functions, alarms and monitors and a full range of interfaces for communications with other systems via various protocols. QnPRH can be scaled to control a single workstation, machine, manufacturing cell or a complete process line.
Communications networking is a critical capability of large scale controllers. The QnPRH is no exception and can be configured for all formats, including peer-to-peer and remote I/O. Examples include dual loop fibre ring networks that maintain control of I/O in the event of hardware errors. And despite all this redundancy, system expansion, development and reconfiguration is, according to Mr Shinton, easier than for any other hardware platform.