Web Servers come in many flavours these days and the majority of manufacturers who incorporate controls in their products have them in some form or another. 'Web Serving' is being promoted as an added value feature to manufacturers products in a wide variety of applications and quite rightly so, as the benefits of using the Internet are now widely accepted within our industry. As products and applications evolve based upon Internet technology, what should end users and integrators look for when selecting a Web Serving Solution? We consider the options and choices available to consultants, end users and systems integrators alike.

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All too often control solutions are selected for historical reasons or to minimise the capital cost of a project. The potential savings to installers from using alternative systems in the engineering and commissioning process are often never considered nor are the potential long term operational savings to the end-user. This results in tight budgets and low margins with inevitable under delivery against customer expectation and reduced customer satisfaction. The ability to demonstrate down the line benefits to end-users can enhance added value and create greater customer loyalty.

WHAT ARE THE CHOICES?

At one end of the scale are Web Servers that provide you with very little other than connectivity to the Internet. An example of this would be a DDC Controller with a 'web server' incorporated; providing little more than an http server and a small amount of memory to store web pages. While at the other end there are extremely comprehensive solutions designed specifically for simple, cost effective implementation incorporating a great deal of functionality 'straight out the box' for many diverse projects and applications. Often, however, many of the 'higher end' solutions are very expensive and difficult to use. This may be acceptable for very large projects, but is unsuitable for small and medium sized projects. The ideal situation is to use a supplier with a range of products all using the same engineering tools where the project can be scaled up without wasting the earlier engineering effort.

There are a number of basic criteria that need to be considered when selecting a web serving solution in order to maximise functionality and user benefits at a cost that is equal to or less than traditional systems. Let us explore these options further:

• Applications
  Does the Web Server provide such functionality as Alarm Handling, Data Logging, Data Presentation and Time Scheduling straight out of the box? These are all required to satisfy the needs of most monitoring / controlling applications via the Internet, using nothing more than a Web browser. Not only should these applications be supported, but it also needs to be understood to what degree any one of these can be modified, added to, and deleted through the Web browser. An example of this would be modifying the time interval that a point was being logged into a database through a data logging application, or adding an alarm with all the necessary alert notification criteria. This functionality is typically known as 'Web based configuration'.

Is there a need to go back to basics and generate script and low level code to achieve the desired application needs such as time schedule changes, add a data logging point or reconfigure an alarm? End-users will not want to be calling out an automation specialist each time they need to add an alarm or change the logging interval on a data logger. Solutions need to be easy to use and manageable by the client after they have been implemented; hence the need to ensure all applications can be managed through 'simple' Web based configuration.

The effectiveness of the data collection, aggregation and presentation is fundamental if maximum benefits are to be obtained from the data provided by the system. Consider what data needs to be seen in the Web browser and how it should be presented. The ability to adapt the solution easily and quickly to changing needs and new situations is essential in the fast moving environment of today.

• Engineering Tools 
  The Web Browser is becoming the User Interface of choice, but how can great looking web pages be achieved and maintained when the Systems Integrator / Controls Contractor has no experience of web page development? The answer is simple. The product must provide the necessary software tools to meet this requirement automatically. Web Servers exist that incorporate engineering tools that can create dynamic web pages of complete applications within 2-3 clicks of the mouse using simple 'drag and drop' principles, with no-requirement for low level coding. Project engineering costs can therefore be substantially reduced as well as providing a flexible and user friendly solution.

• Scalability and Enterprise Management 
  When planning to install multiple Web Servers into an application / facility it is necessary to ensure that there is a strategy to manage them once implemented. A Web Serving Solution needs to be considered that addresses the wider scope of 'Enterprise Management'. Such functions as common Alarm Lists, download of User Names and Passwords to multiple Web servers, project engineering, feature set upgrades and sharing of Client Connections for multiple Web Servers are all key aspects of Enterprise Management. With a truly scalable solution the facility whether local, national or global should never grow beyond the capability of the system to control it. This capability will "future proof" the investment and maintain competitive advantage.

• Thin Client 
  [an error occurred while processing this directive] To maximise the benefits from a Web Serving Solution, it will typically be hook into an existing IT Network. This will need to get the buy-in of an IT department. This aspect needs to be considered very carefully. There are many different ways of displaying data in a web page. HTML can be used in which case the data will be static or an Active-X Control can be used with the benefit of dynamic data but will require software to be loaded onto the Client PC (An IT department will in many cases not allow this). Alternatively a Java based Web server can be used to address these applications. Java has the benefit of being very secure, it's dynamic and it doesn't require any software loading on the Client machine and is also operating system independent (works with Microsoft, MAC, Sun, etc). With a Java based solution remote monitoring, diagnostics and support are available in real time providing maximum control over the application. This enables real-time data to be displayed dynamically in a secure environment, while providing a solution that the IT department will be comfortable with.

• Integration Issues To achieve effective control it is often necessary to monitor and coordinate disparate systems that communicate via a wide range of open and proprietary controls protocol. The web serving solution selected therefore needs to be able to communicate with a wide range of protocols both Open such as LonWorks (LNS), BACnet, OPC, Modbus, SQL, etc as well as various proprietary protocols. Once a higher level solution such as this is implemented the end user has greater freedom to choose different controls vendors as interoperability is addressed through the Enterprise Wide Web Serving Solution.

By carefully considering all of the above criteria it is possible to select a solution that will provide maximum benefit to both the integrator and end-user alike. 

About the Author

Gary Bark Plexus Technology Sales & Marketing Director
Accreditation: Web Serving Solutions and Technology
Location: UK

Gary has been involved in building controls systems for 19 years and have experience in most low voltage control systems found in buildings. Since 1990 his focus has been the International market place which has enabled me to get a detailed understanding of the different technical and commercial requirements on a global basis. Previous employers include Andover Controls and CSI (now TAC).

Four years ago, along with three partners he set-up a controls company Plexus Technology who now specialise in Web Serving Solutions and serves the market globally. The company now has 25 partners, with representation in every continent.

He has also held a position on the LonMark Board of Directors for the past two years.

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