The MAXIFLEX P4D CPU is designed for redundant programmable logic control applications, where high availability is required in hot standby configurations.

A high availability system is constructed by combining two identical P4D CPUs, each with their own Power Supply and Base, to create independent Primary and Secondary Master Controllers. These two Master Controllers are connected to up to seven common Remote I/O Bases through an M1593A/M1594A Remote I/O Network Interface Module, so that both Primary and Secondary Controllers can access the common I/O. A Redundant Ethernet link connects to SCADA or DCS to create a hot standby controller configuration with common I/O.

The Primary and Secondary Controllers in a hot standby system are synchronised every program scan, so that should the primary Controller fail, the secondary Controller can automatically continue program operation from the last Primary Controller scan.

All local data is accessible from a SCADA system through up to 1,000,000 Data Interchange Registers in a single “Data Interchange Table (DIT)” for ease of communications.

All system configuration data and dynamic data can be read and written through this convenient table interface.

The P4D can be programmed in any of the five standard IEC61131-3 programming languages using the Omniflex ISaGraf Programmers Workbench, although conventional remote I/O systems can be implemented without the need for any programming.

The P4D CPU automatically identifies the presence of I/O modules and performs I/O scanning of these modules, making this data available in the Data Interchange Table without needing to write a line of code.

Following the ISO OSI 7-layer model, this 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, quite often without the need to lay special network cabling.

A microSD Card slot provides the ability to log data to file directly from your logic program.

Many other features such as a built-in real-time clock, battery backup for temporary dynamic data.