The changing face of automation

Dave Sutton, Product Manager for HMIs at Schneider Electric, takes an objective look at the way internet technology is bringing about a complete revolution for traditional automation control systems

Ethernet TCP/IP drives the internet and more critical networks than any other protocol, but its use in automation control systems is relatively new. To appreciate the benefits of internet based technologies for connecting HMIs in automation control, it might be useful to take a step back and look at the way they were connected in the past to see some of the problems and limitations that resulted.

Historically, machines or applications were controlled by a PLC and might have had a local HMI display for operator control, the maintenance staff and diagnostics. If two or more identical HMIs needed to be positioned strategically around a machine, it would be necessary to install duplicate hardware and configure second and subsequent HMIs independently.

This was not always straightforward, as there are restrictions such as the maximum number of devices that can be connected to a PLC or network as well as a restriction on the length of the connecting cable. Local HMI connection is straightforward when it only involves connection in a panel but the connection of HMIs at strategic control points several hundred metres away from machinery can increase cost and complexity and lead to less flexibility and, in severe cases, degrade performance.

In automation control systems there is a move towards the introduction of internet based technology, which introduces efficiency by freeing up device connections from hardware constraints. Ethernet TCP/IP was first developed in the mid 1970s and is a tried, tested and proven networking standard. Almost unlimited data and information becomes available to devices connected over a non-proprietary high performance network. Connected devices contain integral web sites on web-servers, and can make their data available on web pages, accessible over unlimited distances. There is no longer any physical restriction on what can be connected to any device, nor any limitation on the distance over which connection can be made.

PLCs now have their own web sites with the same look and feel as any other web site accessible across the internet. This web site can hold information about a machine or application such as standard HMI screens and process information. It can also contain links to electrical or engineering drawings, complete user manuals and other relevant documentation. As well as HMI control and status screens, diagnostic displays and alarm pages, the PLC can show catalogue details and contact information for the nearest local spares distributor or OEM.

Powerful argument

The benefits of Ethernet-based automation control systems are enormous. Devices are accessed using a simple browser, and, providing that the network has been configured to allow it, users can access real-time production data 24 hours a day, seven days a week, from any location in the world. With IT security systems controlling access, authorised staff can get at information immediately, or maintainers can dial in and solve problems from their desk. The manuals can be on the machine, and, if a fault is located, they can organise the spares there and then, and arrange with the production manager and maintenance staff when a fix can be applied. Staff training costs are significantly reduced as the main skill needed for surfing around an automated machine's web site is the ability to use the internet. Time and money saved for the user, and new business opportunities opened up.

Systems will cost less and be easier to modify, as there are no restrictions on the number of devices that can be added to a control system. Additional HMIs are just extra PCs running an internet browser, and they are easy to set up. New technology can be retrofitted to existing systems and modifications are made simply by updating the web site in the PLC. Costs are being continually driven down: connecting a PC or laptop to the internet is virtually free, but each proprietary network card (eg Profibus or Interbus) could cost £1000 or more. For the OEM, being able to offer control systems using the latest technology enhances credibility and gives an opportunity to sell on additional value-added services to the end customer.

There is massive global investment in Ethernet technologies and this continues to drive costs down. Schneider Electric has taken a lead in the incorporation of Internet based technologies for automation control systems and right across its product range web modules have been added in the Transparent Ready programme. Now, many automation, control and distribution products from Schneider Electric have web servers built-in, and control systems are more cost effective, easier to implement and simpler to use. HMIs can now be located where convenient, rather then where it is possible and this is just the beginning. Schneider Electric is leading the way in Web-based automation.

For further details and an information starter pack about Web enabling machines or applications, contact Dave Sutton at Schneider Electric on 02476 847450 or email dave_sutton@schneider.co.uk

• Schneider Electric
  f100@industrialnetworking.co.uk