SOA explained

The most recent buzzword in the IT industry is SOA, short for service oriented architecture. SOA is the current favorite of IT managers, system integrators and IT vendors, yet few managers, integrators, or vendors agree on what it really is. SOA is not a product, technology, or architecture. SOA is just a concept for integrating applications.


The most recent buzzword in the IT industry is SOA, short for service oriented architecture. SOA is the current favorite of IT managers, system integrators and IT vendors, yet few managers, integrators, or vendors agree on what it really is. SOA is not a product, technology, or architecture. SOA is just a concept for integrating applications. Manufacturing professionals should know what SOA is because they will be asked to interface their systems to other systems using an ESB backbone and an SOA model. The ESB is the pipeline between applications, routing messages and buffering requests and responses. SOA defines what travels through the pipe.

The basic SOA concept is that any interface to an application should encapsulate a business service, such as processing a purchase order or performing a physical count of an inventoried material. Calling a service causes the execution of the associated business process. For example, a service may be “assign a storage container ID when material arrives.” The service requires a material lot ID and returns a number for a storage container. The SOA interface could be a service named “AssignStorageContainerID.” The service interface is published to the ESB by the application that assigns container numbers. The application probably performs other processes when assigning the ID, such as recording the assignment, sending the storage number to a warehouse system so that the container is recognized when it arrives, and assigning the container status as “in-use.”

SOA is based on six assumptions: applications are loosely coupled; interface transactions are stateless; interface follows the RPC (remote procedure call) model; interface is message-based; messages use XML data; and interfaces may support both synchronous and asynchronous transactions.

Applications are loosely coupled when the availability of one system does not significantly affect the other system and when the implementation of a service is hidden from the caller. A stateless interface has no implicit history; each use of the interface is based only on the exchanged data and does not use hidden knowledge maintained by the service provider. The RPC model means that the interface looks like a local function or subroutine call and the caller does not have to handle any details of interface messages. A message based interface sends messages between the applications using an ESB, and the messages are based on XML data, not flat files or a proprietary binary interface. The services may be synchronous, in which there is a request for the service and a wait for a response. Alternately, the interface may be asynchronous when the caller makes a service request, continues other processing, and the response comes back later.

These simple SOA concepts are difficult to implement in existing systems. The key is defining the appropriate level and type of services your systems provide. Services can be fine-grained, meaning they perform small actions such as changing one element of data, or coarse-grained, meaning that they encapsulate significant business processes. Coarse grained services are the preferred model for SOA applications, but fine grained services are also often needed.

Manufacturing personnel must assist in corporate SOA initiatives by identifying the critical coarse and fine grained services that manufacturing systems perform. Focus on the business processes that manage the physical control and movement of materials, equipment, and personnel. Coarse grained services will reflect major actions, such as production, testing and maintenance, while fine grained services will handle detailed information on specific materials, equipment, or personnel. Remember that SOA is not an out-of-the box solution; implementing SOA requires a good understanding of manufacturing’s role in the corporate supply chain.

Author Information

Dennis Brandl is president of BR&L Consulting in Cary, NC, .

No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
Each year, a panel of Control Engineering editors and industry expert judges select the System Integrator of the Year Award winners.
Control Engineering Leaders Under 40 identifies and gives recognition to young engineers who...
Learn more about methods used to ensure that the integration between the safety system and the process control...
Adding industrial toughness and reliability to Ethernet eGuide
Technological advances like multiple-in-multiple-out (MIMO) transmitting and receiving
Virtualization advice: 4 ways splitting servers can help manufacturing; Efficient motion controls; Fill the brain drain; Learn from the HART Plant of the Year
Two sides to process safety: Combining human and technical factors in your program; Preparing HMI graphics for migrations; Mechatronics and safety; Engineers' Choice Awards
Detecting security breaches: Forensic invenstigations depend on knowing your networks inside and out; Wireless workers; Opening robotic control; Product exclusive: Robust encoders
The Ask Control Engineering blog covers all aspects of automation, including motors, drives, sensors, motion control, machine control, and embedded systems.
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
News and comments from Control Engineering process industries editor, Peter Welander.
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
This is a blog from the trenches – written by engineers who are implementing and upgrading control systems every day across every industry.
Anthony Baker is a fictitious aggregation of experts from Callisto Integration, providing manufacturing consulting and systems integration.
Integrator Guide

Integrator Guide

Search the online Automation Integrator Guide

Create New Listing

Visit the System Integrators page to view past winners of Control Engineering's System Integrator of the Year Award and learn how to enter the competition. You will also find more information on system integrators and Control System Integrators Association.

Case Study Database

Case Study Database

Get more exposure for your case study by uploading it to the Control Engineering case study database, where end-users can identify relevant solutions and explore what the experts are doing to effectively implement a variety of technology and productivity related projects.

These case studies provide examples of how knowledgeable solution providers have used technology, processes and people to create effective and successful implementations in real-world situations. Case studies can be completed by filling out a simple online form where you can outline the project title, abstract, and full story in 1500 words or less; upload photos, videos and a logo.

Click here to visit the Case Study Database and upload your case study.