Process control needs - all great and small

John Immelman from Endress+Hauser thinks that knowledge, far from being universally commoditised, can and should be outsourced to specialist companies.

For all types of procurement there is a global business trend for organisations to limit and leverage the number of their suppliers of products and services.

However, while one-stop shopping can offer major benefits in terms of minimising accounting and logistics time and costs, streamlining training, implementation and maintenance requirements and optimising returns on investment, organisations should be wary of applying this approach indiscriminately - for example, when sourcing highly specialised goods and services. In such cases, even greater benefits can be gained by dealing with a separate one-stop shop for each different skills requirement.

Despite the increasing trend towards more open and integrated systems, instrumentation and instrument control remain two firmly separated disciplines that involve different sets of skills. On the one hand, instrumentation specialists - who require chemical, mechanical and electrical industry experience - are focused on device hardware and its attachment to pipes and tanks within the process; on extracting accurate, repeatable process data; and on delivering it in one of many formats required by the control system.

On the other, instrument control specialists - who require IT, networking and programming skills - are internal, white-collar workers more focused on automation, PLC programming and SCADA. A single, one-stop shop is thus not ideally skilled to supply both instrumentation and instrument control.

Although some suppliers do offer both types of product, customers inevitably end up dealing with two completely separate, specialised divisions - in effect with a 'two-stop shop'. Furthermore, such suppliers typically promote proprietary instrumentation and control technologies that offer intelligent communication benefits as long as the user remains locked into that vendor. While this creates a seamless network that can be an attractive proposition in terms of immediate problem-solving convenience, customers who go down this route soon discover that their network is incapable of integrating instrument or control technologies from other suppliers at any stage in the future - no matter how desirable they may be in terms of cost, product excellence, performance or service. It therefore seems wiser for process engineers to optimise the flexibility of their system by specifying separate suppliers for instrumentation on the one hand, and for control on the other.

A number of major global PLC/DCS players specialise in non-proprietary control and automation technologies based on Foundation Fieldbus, Profibus, ethernet and/or the new ProfiNet - alone or in combination. These open, freely available bus technologies enable the development of state-of-the-art yet future-proof instrumentation networks that can incorporate any technology from alternative instrumentation suppliers. By going down this route, customers always retain the freedom to choose the best-of-breed instrumentation technologies from any supplier on the basis of product excellence, service and price.

At the same time, it makes sense for process engineers to select specialist, broad-range instrumentation suppliers. In the absence of solid, reliable, state-of-the-art instrumentation, even the best control system becomes redundant and what results is 'rubbish in, rubbish out'. It takes truly committed specialists to research, develop and support revolutionary new measuring technologies such as guided microwave for level, Coriolis flowmeters for viscosity and contactless pH electrodes, with major investment, breadth and depth of expertise and a 110 per cent focus on design optimisation.

The successful set-up and ongoing usage of any new process instrument demands effective support from within the organisation as well as from the vendor. Trained staff must familiarise themselves with the technical manuals, successfully use the configuration software and master the day-to-day operation of the user interface. Given the wide variations in operating systems and user interfaces between instrument suppliers, the greater the number of sources of supply the more complex and confusing these responsibilities can become. In contrast, an organisation that sources all its instrumentation from a single supplier only needs to deal with a single user interface. This streamlines both the commissioning of individual instruments and the coordination of those instruments within the organisation's instrumentation network - enabling major savings in staff head-hours and expensive process downtime.

Process instruments are typically fitted in robust operating environments. This results in high levels of wear and tear and strong demand for ongoing maintenance and repairs. Organisations that deal with a single supplier gain the advantage of just one point of contact into a comprehensive maintenance service, via a single technician who can understand and trouble-shoot not just the instrument in question but the network as a whole. In addition, the more an organisation leverages from a particular supplier, the more time and resources the supplier will be able to dedicate to that particular customer's needs.