Electricity + Control October 2017

3& :RU[ (QJLQHHU Adaptive Software Platform

abbreviations

FBD – Function Block Diagram IT – Information Technology LD – Ladder Diagram SDK – Software Development Kit SFC – Sequential Function Chart ST – Structured Text

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PC Worx Engineer tailors the functional scope to requirements, ensuring added cost-effectiveness.

T he PC Worx Engineer adaptive engineering software by Phoenix Contact – PLCnextTech- nology – is a cornerstone of the solution. This tool combines the most important functions of an automation solution and systematically expands capabilities for simultaneous project development. Additionally, PCWorx Engineer tailors the functional scope to requirements, ensuring added cost-effec- tiveness. IEC 61131-3 [1] has been the international standard for programming in the field of automation for decades. Tools from a variety of manufacturers reflect the structure of this standard and allow the user to easily develop application-specific automa- tion solutions. Compared to older solutions, today’s solutions have become significantly more complex with the integration of technologies such as func- tional safety, visualisation concepts or different pro- gramming languages outside of IEC 61131-3 [1]. As a result, project teams have to manage and master an increasing number of disciplines. This means that different programmers usually work simulta- neously on the same project or project task, and often in different disciplines. The team members then merge the different project results together into the master project at defined intervals. To do this, they often use common version control tools such as Subversion or GIT. Clear assignment of permissions With conventional automation tools, projects are stored in folder structures according to the hierar- chy described in IEC 61131 [1] and are transferred to version control tools in this format. In such tools, rights can be assigned to individual objects. How- ever, changes to an object that is visible to a user usually result in modifications in all folder struc- tures. The user is unable to track these changes. For one, this goes against the principle of privilege separation. Second, even tools like GIT cannot of- fer reliable protection against manipulation in such cases. Furthermore, it is possible for competing versions to be saved with different changes (see Figure 1 ).

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This company ensures that users pay only for the services they need to implement an auto- mation project. The basic version of PC Worx Engineer can open all projects. Its flexibility makes it possible for users to fo- cus on the project rather than the software.

Project X

1

State Welding Coating

IEC 61131-3

Time

Version 1

Function block Main task Welding task Coating task Function

Copying Version 1 to systemA Copying Version1 to systemB

Modifying

Modifying

2

Visu

Copying themodified version to the server

Welding Coating Overall operation

Version 2

Conflict

Copying themodified version to the server

Version3

3

Version 3 (modify by )

overwrites Version 2 (modified by )

Is this acceptable?

Figure 1: Points of conflict in a conventional folder structure.

To solve these fundamental problems, the com- pany developers have borrowed an approach used by the military. In the military, geographical areas of responsibility are strictly assigned to specific command posts. This structure ensures quick re- sponse times in each area of responsibility, thanks to defined authorisations. Fewer communication interfaces make operations more efficient, and by restricting responsibility to one person, misunder- standings are prevented, thereby minimising the likelihood of errors. So how is this approach implemented in the new PC Worx Engineer software? The project manager assigns developers responsibilities for individual applications in the usual way. PC Worx Engineer creates the folder structure of the project based on the assigned responsibilities. If a devel- oper makes changes to the program, the software only makes the changes in that developer’s area of the folder structure. The other parts of the master project remain untouched. While this procedure is not discernible to the user, this type of folder structure allows for clear separation of privileges. All privileges, from the folder level (IT administrator) to the develop- ment tool level (project manager), can be easily and clearly assigned using this method (see Fig- ure 2 ).

The editors in PCWorx Engineer provide users with so-called inplace actions. These buttons always appear in a context-sensitive manner when a defined action is possible on an object, and are placed graphically directly next to the object. Searching for actions in toolbars becomes entirely obsolete and editing code and graphics becomes much more efficient.

12 Electricity + Control

OCTOBER 2017