Working under increased pressure

Fisher-Rosemount pharmaceuticals specialist Nick Taylor looks at developments which will help pharmaceutical manufacturing plants to manage the pressures of getting products to market

There has been a rapid introduction and acceptance of recent developments in control systems for batch process plants, with manufacturers in the medical and pharmaceutical sectors, among others, seeing the benefits of adopting a field-based architecture.

Traditionally, diagnostic systems have been proprietary and application specific, with little benefit outside a narrowly defined piece of equipment or process, and lack real data from the process system, or the devices they are designed to monitor. Field-based architectures such as Fisher-Rosemount's PlantWeb use the computing power available in intelligent field devices, such as flowmeters, pressure transmitters and control valves. As well as improving functionality, lifetime costs are lower for these systems which are simpler, cheaper and faster to implement, more quickly commissioned and have a lower maintenance overhead.

Using a field-based architecture, fieldbus links are looped between devices rather than having single twisted pairs to each transmitter, all wired back to the control room. The field-based architecture combines advanced diagnostics and control in the field to address many current limitations and provide an unprecedented opportunity for improve financial performance. In a field-based system, communications between devices are monitored and information about plant and processes is collected so faults can be detected and diagnosed. The control system then provides the operator interface which accepts instructions and integrates with other applications around the enterprise using open protocols. The advantages this brings are not only restricted to new plants, but can be used to enhance existing equipment, bringing the benefits of modern instrument capabilities as they are then installed on new sections.

Improved performance A field-based architecture uses the power of field intelligence to improve plant performance. Over the last several years a combination of increased computing power in field devices, higher performance in device sensors, and a fully capable and standard communications protocol, Foundation Fieldbus, have enabled field devices to deliver a step increase in functionality and value. These factors may change the fundamental definition of a process automation architecture, and process control.

Field devices today can perform functions including (but not limited to) closed loop basic and advanced regulatory control and discrete control. These devices can also perform statistical process monitoring. In addition they can detect and calculate both actual process variability, and theoretical minimum variability. Improved sensors can detect process conditions over a broader frequency range and with greater accuracy and repeatability than in the past. This information reveals fundamental process signatures such as drift, bias, noise, stuck, and spike. These signatures combined with process control information can then be used to detect a wide variety of equipment and process conditions ranging from remaining sensor life, or plugged impulse lines, to control abnormalities with flow, temperature and level loops, to operational or performance problems with process units. This value can only be extracted, however, if the automation architecture can access and use the information in a coordinated way.

In the past plant engineers have approached efficiency by implementing optimum process control systems but an increase in economic efficiency cannot be reached simply by providing better control schemes.

• Fisher-Rosemount
  a142@industrialnetworking.co.uk
  
  

Improving plant availability and increasing efficiency come as a result of early detection of anomalies and the resulting condition-based real-time maintenance that leads to improved availability. Traditional automation architectures are not capable of accessing, using, or delivering this functionality. They are designed to access a single value, or a value and basic status from a field device, then delivering that information to the process control system for closed loop control and monitoring. They are not designed to deliver control information such as mode, alarms and setpoint changes, or other control information back to field devices for use or analysis.

Smart devices The use of smart field devices has the advantage of providing accurately time stamped information directly to the control system as anomalies develop. Control systems based on a field-based architecture are fundamentally different in their ability to access and use this information. Data analysis is partially or completely done within the devices themselves which significantly reduces communications bandwidth requirements. Using pattern recognition and statistical analysis methods, devices can now detect various process anomalies such as drift, bias, noise, spike, and stuck behaviours for each process. Furthermore, information available to the raw sensor but not to the system can be used to perform analysis not possible in any other way. By combining this information with process control actions such as mode, setpoint and load, plant operators can for the first time gain fundamental insights to the health and performance of both their equipment and processes. Operators are also able to take corrective steps faster and avoid conditions which could cause a process upset or shutdown.

With a higher degree of control and more information available in the system, the next logical step is to integrate control system functionality with higher level systems and use the power of this integration to drive the business towards achieving new targets. And built on control systems using field-based architecture are the asset management, production batch control and electronic documentation systems necessary to an industry with strict global regulation and extreme competitive pressure.

The pressures on pharmaceutical companies in particular will always be severe, both in terms of competition and regulation. But efficient and well thought-out control systems can be a make significant improvements to manufacturing operations at a number of levels. Faster commissioning of instruments, calibration procedures that meet the specific requirements of the pharmaceutical industry and automated documentation all play their part, and alongside these the establishment of a predictive maintenance regime demonstrates how the field-based architecture provides the facilities the pharmaceutical industry is looking for.

 

Purpose built facility Fisher-Rosemount and Bristol-Myers Squibb have recently announced a contract to provide a Process Automation Solution on a major new greenfield pharmaceutical plant to be constructed near Dublin. The project, known as the Cruiserath Bulk Manufacturing Facility, is for multi-purpose batch manufacture of health care products, and will involve over 1000 instrumentation and control points. In particular Rosemount pressure, temperature and flow instrumentation will be supplied as part of the initial order. All equipment will be intrinsically safe or flameproof, and the key networked intelligent field components will transmit information, especially plant equipment diagnostics, using HART and Foundation fieldbus communications. The PlantWeb architecture will include AMS (Asset Management Solutions) as a key module so information from field devices can be used as an integral part of plant asset management. Caption: A DeltaV automation system operator in the control room at Pfizer, Ringaskiddy, Ireland. Pfizer has several PlantWeb installations in its plants in Cork and Sandwich