XML Control Logic Standard Gains Acceptance as Digital Factory Interface

XML Control Logic Standard Gains Acceptance as Digital Factory Interface

by Bill Lydon
Managing Director, PLCopen North America
 
Open non-proprietary interface allows users to pick the best of breed production hardware and software including PLC, PAC, PLM, modeling, and simulation software to make virtual design and production simulation a reality.
 
The PLCopen organization’s XML standard (www.control-xml.com) provides an open, non-proprietary, software interface for the interchange of industrial and process control programs between controls, Product Life Cycle Management (PLM), Machine & Process Simulation, CAD, documentation software, and other systems.
 
Innovations in Product Life Cycle Management (PLM), modeling and simulation software are enabling virtual designs of machine, production lines and processes to avoid costly mistakes in actual implementation. The entire virtual plant and controls can be commissioned virtually to find problems before committing to real machines and controls reducing the time it takes to start manufacturing process and avoids costly rework at production startup time.
 
Free XML Standard Documents
 
The PLCopen XML schemas and documentation as well as an introduction are available free to anyone on the internet at www.control-xml.com The downloadable files include a 156 page Explanation of the PLCopen XMLSchema, 58 page document on XML Formats for IEC 61131-3, and XML Schema files.
 
The PLCopen standard has gained acceptance by the AutomationML organization www.AutomationML.org. The AutomationML group accepted the PLCopen XML format for the description of control. This cooperation closes the gaps between production design (virtual factory) and the shop floor resulting in reduced time to market and lower costs for manufacturers. A number of PLCopen member companies are supporting the XML standard including independent software suppliers 3-S, KW-Software, and KirchnerSoft. 
 
PLCopen’s XML standard provides an open non-propriety linkage to control system that has not been available until now. The only option leading edge manufacturers had before this development was to develop their own software creating interfaces to a single vendors proprietary control products. This could only be done on large projects at high cost and with the compromise of being tied to a single control vendor. PLCopen’s XML standard now provides an open playing field to lower costs and foster innovation in the same way open industrial networks, CAD interchange standards, OPC, and other standards have already done.
 
The PLCopen XML standard capitalizes on the open IEC 61131-3, Safety, Motion Control, and other standards to support virtual design and production. As a result, manufacturers can expect to reduce the cost of engineering and ramp-up time, and continually optimize their manufacturing operations with accurate, real-time, simulation models.
 
Background information
 
Since the release of the IEC 61131-3 programming standard, users want to be able to exchange their programs, libraries and projects between development environments. Although this was not the intent of the standard itself, it was a task that the independent organization PLCopen committed itself to.  
  
IEC 61131-3 is focused on the software development environment. As such it is just a part of a total solution. The other parts are a structure of tools like: network tools, debug tools, simulators, documentation tools, etc. Therefore PLCopen has decided a few years ago to realize interfaces towards these support tools. This resulted in a workgroup named TC6 for XML (eXtended Markup Language). This committee defined an open interface between all different kinds of software tools, which provides the ability to transfer the information that is on the screen to other platforms. This screen information does not only contain textual information, but also graphical information, like where the blocks are and how they are connected.
 
User Perspective
 
PLCopen wants to accomplish this without much additional effort. A project can be transferred from one development environment to another, without losing information, even when it is incomplete, e.g. not compatible without errors. This of course is also valid for the POUs, and especially for User Derived Function Block libraries. This means that the program itself has to remain the same, so not be altered during this transfer. The big variety of possibilities has to be brought under one umbrella. And XML provides the right technology for this.  
The result of the PLCopen XML work opens the development environment by providing interfaces to other software tools.
 
As such it will be more than an export / import tool from one development environment to another. From the moment onwards that this format is available, it is just a small step to feed for instance a documentation tool with the information. Actually, it is not important where this XML-code is coming from as long as it is recognizable and useable. So it could be generated by other tools like simulation and modeling tools, and consumed by verification, documentation, and version control tools.
 
In principle all relevant information will be exported. The importing tool has to be intelligent in filtering which parts of this information is useful and needs to be imported and used. With this PLCopen creates a complete new market, in which the focus is on reusability of software developments up to whole projects.
 
About PLCopen
 
PLCopen was founded in 1992 and is a worldwide not for profit organization dedicated to improving the automation programming efficiency and productivity in the controls industry. PLCopen efforts are focused on control software standards that harmonize industrial control programming worldwide.  www.plcopen.org
  
PLCopen members are leading industrial automation companies including Siemens, ABB, Baumuller, Beckhoff, Bosch Rexroth, B&R, Digital, ProFace, ELAU, GE Fanuc, Honeywell, Mitsubishi, Omron, Parker Automation, Phoenix Contact, Rockwell Automation, Schneider Electric, 3-S Software, ICS Triplex ISaGRAF, Yaskawa, and Yokogawa to name a few.