PLCopen has started a new activity in cooperation with CAN in Automation. The kick-off meeting for this event was held in February 2012.
During this meeting the goals were defined and the first ideas were generated. Increasingly machine builders are faced with distributed control systems, in particular in medical devices, in mobile machinery, and in modular machines.
In general, you can design distributed control systems with IEC 61131 compliant controllers. However, you need some manufacturer-specific additions to achieve this.
In order to close this gap, PLCopen and CiA call for experts to address the necessary functionalities. This includes the standardisation of communication mechanism for starting and stopping other controllers, to share computing power and other resources, to support fault tolerant systems, and to react on events generated by other controllers.
PLCopen is a vendor- and product-independent worldwide association. Its mission is to be the leading association resolving topics related to control programming to support the use of international standards in this field.
One of the core activities of PLCopen is focused around IEC 61131-3, the only global standard for industrial control programming. It harmonises the way people design and operate industrial controls by standardizing the programming interface.
A standard programming interface allows people with different backgrounds and skills to create different elements of a program during different stages of the software lifecycle: specification, design, implementation, testing, installation and maintenance.
Yet all pieces adhere to a common structure and work together harmoniously. The standard includes the definition of the Sequential Function Chart (SFC) language, used to structure the internal organization of a program, and four inter-operable programming languages: Instruction List (IL), Ladder Diagram (LD), Function Block Diagram (FBD) and Structured Text (ST).
Via decomposition into logical elements, modularisation and modern software techniques, each program is structured, increasing its re-usability, reducing errors and increasing programming and user efficiency.
[Image at the top right courtesy Invensys.]