Dual redundant programmable automation controllers

Edited by the Processingtalk editorial team Apr 13, 2006

The Maxiflex P3-R CPUs are designed specifically for redundant remote I/O and control applications, where high availability is required in hot standby configurations

The Maxiflex P3-R CPUs are designed specifically for redundant remote I/O and control applications, where high availability is required in hot standby configurations.

The high availability system is constructed by combining two identical P3-R CPUs, each with their own power supply and base, to create independent primary and secondary master controllers.

These two master controllers are connected to common remote i/o bases, and to the SCADA system to create a hot standby controller configuration with common I/O.

How it works:- both controllers consume the common input data from the remote I/O bases, but only the active controller controls the outputs, and communicates with the supervisory computer.

The secondary controller continuously monitors the health of the master controller, and if a failure is detected, then the secondary controller takes over control.

The primary and secondary controllers stay synchronised through a separate communications link between the two controllers.

The monitoring, and switch-over between primary and secondary controllers occurs completely transparently to the SCADA computer.

The secondary controller can either run a programme identical to the primary controller, or it can run an independent programme designed to bring the process to a safe state.

The P3-R can be programmed in one or more of the standard IEC61131-3 programming languages (all 5 languages plus flow chart and PID auto tune)using the Omniflex ISaGraf Programmer Workbench, although conventional remote I/O systems can be implemented without the need for any programming.

The P3-R CPU includes a powerful inter-network routing capability for retrieving data from the corners of the factory in very large, geographically spread-out installations.

This capability allows many dissimilar network types to be linked to create a seamless factory intranet, often without the need to lay special network cabling.