Tag Archives: Innovation

OPC UA Makes Highly Distributed Network Control Systems Possible

Integration

Nowadays, to be on edge, modern manufacturing automation systems have to be involved. Usually they consist of numerous different IT systems located at business management/operation and process control levels. It is broad class of applications domain where business IT and control systems are converged to make a large whole with the aim to improve performance as the result of the macro optimization and synergy effect. This domain is called Industrial IT. Frequently the systems are distributed geographically in multi-division organizations.

To deploy the mentioned above convergence the systems have to be integrated – must interoperate with each other. From integration we should expect improved performance as a result of synergy and macro optimization effects.

After integration the systems should make up a consistent system, i.e. each subsystem (as a component) must communicate with each others. The final information architecture is strongly dependent on organization, culture, type of technology and target process. Communication is necessary for exchanging data for production state analysis, operation actions scheduling, supervisory control and task synchronization in the process as a large whole.

Vast majority of enterprises declare that difficulties with the integration of the existing systems are the most important obstacle to expand the process control and business management support. Other major integration problems are diversification of the existing systems, their quantity and non-unified data architecture.

Integration process results in Large Scale Distributed Network Control Systems (LSDNCS). Systems belonging to this class are usually created in a multi-step integration process. To succeed, the process has to be governed by a well-defined information and communication architecture.

Integration Models

System integration means necessity of the information exchange. To exchange information we need an association between components. Going further, to instantiate association, i.e. to make the component interoperable, we need at the same time a common:

  • information representation –  a language (data type),
  • underlying communication infrastructure – a transport (protocol + medium),

We must be aware that establishing an association we are actually building information architecture – system structure. It is worth stressing that selection of the architecture development has a great impact on the final robustness, maintainability, expandability, dependability, functionality, and last but not least implementation costs.

Generally we have three possibilities:

Peer to peer approach: Common integration practice is to achieve short-term ad-hoc objectives by manually creating/proprietary dedicated point-to-point links between the subsystems everywhere it is useful (see fig. 1). Using randomly this approach we can establish numerous independent links ((k+n)(n+k-1)/2 where k, n – number of business and process control components appropriately). The number rapidly grows, e.g. it is equal 1770 links for n=10 ; k=50, and finally we have to deal with rapidly growing complexity leading to the communication chaos, which is difficult to be maintained.

In this model the information and communication architectures are closely coupled. This approach is very popular, but adversely affects all of the solution features.

Peer to peer approach

Fig. 1

Totalitarian approach: One option to overcome the communication chaos problem is to use an “all in one” product dedicated to both functions: process control and business management (see presentation). Usually, it is provided as one complex, total system – let’s call it a supper-system. Most of the MES (Manufacturing Execution System) vendors offer theirs products as a panacea for all problems of the chaotic system integration.

Actually supper-system does not solve the problem, it only hides it under a not transparent cover and makes the solution very difficult to expand and vendor related forever.

In this model the system distribution is reduced, and as a consequence many associations can be instantiated on the same platform without necessity to communicate. This model reduces complexity by reducing communication needs.

If strictly observed it could be a dead end.

Process Observer approach: The Process Observer is a consistent, homogenous real-time representation of the process control layer. It is a kind of the virtual layer, which is a “big picture” of the underlying process layer composed of unit data randomly accessible by means of a unified and standardized interface (see presentation). It allows sharing data from plant floor devices by the process and business management systems, using international standards of data exchange. Process Observer is like a bridge connection between the plant-floor control and the process and business management levels.

Thereby, the structure of the links becomes systematic and the existing functionality of the upper layers is preserved. Now, they can gather the process data in a unified, standardized way (see fig.2).

Using the Process Observer archetype the number of links between components can be substantially reduced and, what is very important is a linear function of the number of nodes.

Process Observer model greatly reduces the whole complexity and decrease dependency by decoupling application associations and underlying communication routes. Additionally, it allows applying systematic design methodology and building information architecture independently of underlying communication infrastructure.

Fig. 2

Fig. 2

Related articles

Real-Time Communication for Large Scale Distributed Control Systems (Proceedings of the International Multiconference on Computer Science and Information Technology pp. 849–859 ISSN 1896-7094)

Process and business layers robust integration (white paper)

Communication management in the Process Observer Archetype (Proceedings of the 16th conference “Polish Teletraffic Symposium 2009”)

Large Scale Distributed Process and Business Management Integration (Proceedings of the 14th International Congress of Cybernetics and Systems of WOSC)

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Embedding Agile Principles as Contract Rules

Agile management is recognized as a methodology that helps us to guide software development projects towards the most valuable outcome possible. The methodology well accommodates inevitable unpredictability of the project that adversely affects the expected results and workload assessment. It is, therefore, a good candidate to be applied to high risk innovative research projects based on a contract. Methodology extension and tools based on the business processes modeling are proposed with the aim of harmonizing and embedding agile principles as contract rules.

This proposal is based on the experience gained while managing variety of innovative process control and business management projects. For these and similar projects, their scope definition and budget estimation in advance have always been the most challenging task. Typically, if the estimated budget of any project is higher than the other ones, the solution provider is recognized as inefficient in one way or another. But there might be another reason if innovative projects are concerned, i.e. the provider’s know-how and extraordinary experience make a better assessment possible. Better always means higher in this context and, in a typical bid where budget is the most important factor, it puts the solution provider in an underprivileged position and leads to the “more stupid the better” syndrome.
For an innovative project, the main reason why its critical parameters are hardly predictable is its innovative nature. From the definition, an innovation as a translation of an idea or invention into a product or service that creates value is an exploration into unexplored areas. The leader of the team must, therefore, face up to a high level of uncertainty.

The main aim of any invention result application is to further satisfy the needs and improve selected processes. But in all cases it is a business process involving at least two organizations: a customer and a solution provider that must cooperate under a contractual relationship, i.e. a voluntary, deliberate, and legally binding agreement between them. The contractual relationship is evidenced by an offer, an acceptance thereof, and a valid (legal and valuable) consideration.

To make the procurement process transparent, fix-price and fix-term offers are usually expected to simplify the comparison and selection of a bid for contract award. As a consequence, the quantitative nature of the comparison relaxes the responsibility of the target company (customer) management involved in the selection process, which makes the selection process offer centric and neglects uncertainty of the proposed terms. In some circumstances it could cause an assessment of just a “wish list”, but not a realistic proposal and leads to circular impossibilities:

  •  It is impossible for the customer to prepare the specifications because it is unaware of the necessity of exploration.
  • It is impossible for the solution provider to prepare the offer as the specifications are inadequate and the unanswered questions can be addressed and worked out as project goals only.

The procurement issues described above could be partially solved using direct negotiations or the single-source acquisition method. Unfortunately, both “suffer from” the qualitative nature of the selection process and usually are an exception to the typical procedure. Nevertheless, as the quantitative assessment is difficult or even impossible, they might be a better choice.
The discussion about the procurement process is out of this post scope. However, in spite of the selected procurement method, the question how to limit the budget, determine the time frame and define the expected scope and quality in the contract is still open.

A new methodology is required to address this question. Its implementation should be non-invasive and effortless but, if strictly observed, it must control the development process to minimize the price-to-performance factor and assure meeting of the customer basic requirements.

For the problem described above, I propose a methodology framework that tightly couples:

  • Agile management to dynamically control the work scope and time framework.
  • Workload tracking to precisely control the value for money.

This method is also proposed to be deployed using supporting tools developed on the process model basis to make the deployment straightforward.