Automation services from the cloud

New trends in process control systems feature the application of new ICT technologies and an emerging architecture for automation systems based on web technologies. The architecture is designated as a Web- Oriented Automation System (WOAS), following the approach of a web-oriented architecture (WOA) familiar from IT. Reinhard Langmann explains how the WOAS architecture allows the transfer of principles and methods from the standardized world of Internet technologies to the world of industrial automation.

In a cloud-based platform for building automation developed by Digi International, sensors and actuators are integrated as embedded systems (M2M devices). The cloud infrastructure provides remote device management and cloud-based information exchange with integral SCADA functions.

FROST & SULLIVAN'S 2012 study predicting cloud computing will go mainstream essentially envisages five different megatrends for the factory of the future: cyber security, mobile and wireless technology, companyspecific ecosystems, cloud computing and sustainability.

Emphasis on the product portfolio of industrial automation is expected to decline over the next few years. In contrast, the requirement for globalized service & support is set to gain importance, together with the cost factors. The introduction of secure cloud computing technology enables access to relevant strategic data via the Internet, which can be used to make decisions in real time as well as boost the operational efficiency.

The classic automation hierarchy is increasingly becoming transformed into a flat automation cloud where two new technologies/ paradigms are used: service-oriented architectures (SOA) and agent technology. Both strategies provide the option of creating uniform interfaces while allowing collaboration from the field to enterprise levels. This means a high and cost-efficient throughput can continue to be generated despite rising individuality, complexity and quality.

The trend towards a spatial and functional distribution of automation functions is by no means new. Solutions up until now have always focused on proprietary solutions specialized in automation technology, which nevertheless met with little success owing to their complexity and inadequate industrial support (e.g. CORBA). It was not until the new and standardized IT-technologies based primarily on the Web/Internet that the prerequisites for a spatially unlimited distribution of functions/ services were establishing, these now also of interest to automation technology.

Comparison chart shows the essential features of a standard web-based SCADA/DCS system in contrast with a system based on the WOAS architecture.

This trend will have a rapid and significant effect on process control technology which by its very nature involves superordinate and coordinating automation functions, and is already associated with scheduling and distributional tasks. Moreover, functions of the control level tend to have a "soft" real-time performance that can be realized with modern web technologies (operating & monitoring, data analysis etc.)

Services from the cloud

Cloud computing is the provision of jointly usable and flexibly scalable IT services using IT resources via networks. Typical features are provision in real time as a self-service based on Internet technologies and charges according to use. Cloud computing enables users to redistribute from investment to operational expense, while paving the way for completely new business models and their prompt implementation.

The classic automation hierarchy is increasingly becoming a flat automation cloud incorporating service-oriented architectures (SOA) and agent technology.

Services from the cloud are divided into three levels:

Applications as a service (software as a service - SaaS): Examples here are Google Apps and Microsoft Online Service. Hardly any applications are so far available for tasks involving process control technology.

Technical frameworks as a service (platform as a Service - PaaS): The Google App Engine and the Microsoft Azur Service are examples of this. The first examples are also apparent in the area of M2M communication mainly for building automation with (iDigi).

IT-based infrastructure or hardware components as a service (infrastructure as a Service - IaaS): Examples of this can be seen in Amazon EC2 as well as the MS Windows Azure platform. The first automation technology applications typically use the MS Windows Azure platform such as the data evaluation of a wind farm with Beckhoff controls.

From function to automation service

Service-oriented architectures (SOA) that implement the automation functions of devices and systems are required for the use of cloud services in automation. A number of effective approaches are already being researched in Europe. These include SOCRADES, which examines the use of web services and SOA below the management level. The system looks at integration of web services in automation devices and implementation with DPWS (Device Profile for Web Services) and OPC UA.

A second example is IMC-AESOP which is potentially an SOA-based solution for the next generation of SCADA/DCS systems targeting large distributed automation applications.

Plus, there are also major endeavours to find solutions for the use of service-based cloud structures for control technology and processoriented areas in the field of patent law. These include the following solutions:

Method for the development of a multi-agent system: SOA in automation technology; devices provide their services among one another (2009, Schneider Electric Automation).

Cloud computing for an industrial automation and manufacturing system: A client is able to determine whether a process is suitable for outsourcing to a cloud and whether it can perform this outsourcing (2009, Honeywell).

Method for the integration of at least one field unit in an automation technology network: Integration of any automation devices by creating a virtual map and utilization of the cloud computing (2010, Endress+Hauser)

In particular, cloud utilization as PaaS is currently already being applied in building automation. Here sensors and actuators are integrated as embedded systems (M2M devices) in a cloud infrastructure for remote device management and cloud-based information exchange with integral SCADA functionality.

However, all previous available solutions and approaches do not consistently utilize modern web technologies and enable hardly any cloud applications as services for automation solutions (SaaS). Moreover, these systems have the following further drawbacks.

The devices are not integrated via industry standard interfaces such as OPC. Additional and expensive hardware adapters are usually required as an M2M interface. The cloud platform is proprietary, being operated exclusively by the provider and providing only the services made available by the latter. An extendibility to and/or integration of third party service providers is not envisaged.

All process data of users is located at the provider (often abroad), who is responsible for its administration. The service charges are generally flat rate for use of the platform or according to the number of integrated customer devices. Automation services cannot be charged specifically.

Basics of the WOAS architecture.

Component structure of the WOAS kernel.

The WOAS project

Taking the state of the art as a starting point, ten automation companies were involved in the proposal to research an application- oriented, "lean" and open architecture for an automation system that utilizes cloudbased web technologies consistently while providing a well-defined structure as a model for a flexible implementation. The project entitled WOAS (Architecture and Interfaces for a Web-oriented Automation System) is funded by the BMWi (German ministry of economics) as an Industrial Joint Research project (IGF) with term of 2.5 years from September 2011.

The aim of the WOAS project is to research a new architecture for automation systems based on web technologies. The WOAS architecture allows the principles and methods from the standardized world of Internet technologies to be transferred into the world of industrial automation in a systematic and structured manner. A WOAS consists of a WOAS kernel as well as a configurable number of web-oriented automation services (WOAD) that implement the required automation functions.

As a further objective, new business models are to be researched, which enable an efficient use of distributed automation functions based on the WOAS service structure.

Within the principle structure of a WOAS, the automation system is created free from an XML design specification (SK = system kernel) in the web browser, and the SCADA/ DCS automation functions (AF) are used as automation services (AS) via a WOAS cloud for a set price. The real time AF are running as always in the hardware-based field system (such as a PLC). The field systems (devices) are connected via standard industrial interfaces. All elements of a WOAS including the engineering system (WOS creator) can be accessed via the web.

The following further results or properties of a WOAS are aimed for in the project. This includes development of a system kernel that can be dynamically generated as an XML design specification for an automation system with well-defined interfaces.

Other goals are the combination of cloud technology with SOA-based automation services, development of a clearing system for charging for fine-grained services according to the SaaS principle and integration of mash-up technologies (Web 2.0) in a hybrid service structure (connection of a server-based structure with a web-oriented structure).

A final group of objectives includes examining the security of hybrid cloud solutions (public cloud/private cloud) for rights matching, authorization and access protection; integration of standard field systems via standard protocols (OPC DA, OPC UA, MODBUS without integrated web service); and use of automation services of different providers in a WOAS using open interfaces.

Prof. Dr.-Ing. Reinhard Langmann, FH Düsseldorf, Competence Center Automation Düsseldorf (CCAD)

FH Düsseldorf, Competence Center Automation Düsseldorf