PLC architecture takes in process and motion control
15 Jan 2000
Described as the `next generation control system architecture for PLC, motion and process control,' the Allen-Bradley ControlLogix system is at the heart of Rockwell Automation's new mid to large range PLC.
Rockwell says that, unlike conventional programmable controllers, the ControlLogix system is designed with communications at its core. A passive data bus allows users to integrate sequential, drive, motion and process control onto a single platform. Multiple processors, networks and I/O can be mixed on a single chassis. As the system grows ControlNet will allow control to be distributed to additional chassis.
The key to the system is the Logix 5550 controller, which is easily programmed to IEC 1131-3 specifications while retaining the look and feel of existing Allen-Bradley products, without any need for users to pick up on different programming skills.
The 5550 also offers integrated motion control by simply inserting standard motion instructions within the controller's motion ladder diagram. There is only one software tool to learn and one program to maintain.
Process capability is added to the ControlLogix architecture with the Honeywell-developed ProcessLogix processor. This is a high performance CPU offering DCS capability. The tight integration of the ControlLogix architecture is said to make the system ideal for those applications that require both sequential and process control in the one package.
