In this era of global competition, manufacturers in the process industries are being driven to achieve operational excellence to secure their place ahead of their competition now and in the future. Selection of new automation technologies impacts this goal. Consequently, the selection process is more important to a company's staying power than ever before. In fact, the importance of the selection of technology far outweighs the cost of the automation investment itself.
Selecting the right technology and the right supplier can help your company:
• respond quickly to changing market conditions in a way that creates a sustainable competitive advantage
• minimize Total Cost of Ownership (TCO) over the life of your plant
• create a system which is easily maintainable/upgradeable for the long-term
• achieve its future goals and vision
Selecting a system of automation based on a review of available products is the typical course of action for someone in the market for a new automation system. The problem approach is that your perception of which systems "make the cut" is often based on old stereotypes or influenced by the claims of the first salesperson in the door. Let's look at the components of a DCS or PLC based system to see how different (or similar) they really are.
At first glance, the pictured system architectures look very similar. Both systems share the following components:
• Field devices
• Input/output modules
• Controllers
• Human Machine Interface (HMI)
• Engineering
• Supervisory control
• Business integration
As you look at the following system architectures, you should note that the technologies used in each system are in fact, very similar; the difference becomes more apparent when you consider the nature and requirements of the application.
For example, in the DCS architecture diagram, redundancy is often employed for I/O, controllers, networks, and HMI servers. Since redundancy adds complexity and sometimes cost, DCS users must carefully evaluate their need for redundancy in order to achieve their required system availability and to prevent unplanned downtime.