Developments in process control are fundamentally changing the way paper is made and creating new opportunities to boost quality and efficiency

Staying in control with the latest process tools

Operators keep their distance with Neles Automation’s Field Browser

Ironically, as the suppliers become more closely knit, their products are going in a very different direction - out in the open. As Antti Kaunonen, professor of pulp and paper automation at Tampere University, Finland, puts it, "A definite trend is from a proprietary distributed control system to an open Application Platform. Openness is achieved through the use of industry standards. Control, engineering and management information are integrated together in the Application Platform."

This view is echoed by Matti Pulkkinen of Honeywell-Measurex. As he explains, "One of the main trends in process control is that systems will be more open. How the suppliers and customers can utilize this openess in real life will be one of the future trends. Operator interfaces and fields will be more open and there will be less conventional cabling".

Honeywell-Measurex's answer to the challenge of working in a 'open' environment is the Da Vinci Quality Measurement and Control system. The Da Vinci system includes a range of scanning and non-scanning measurements, which offer increased scanning and processing speed as well as higher resolution. The added attractions of the new system are its "fully open architecture which supports OPC and the advances in sensor technology", according to Pulkkinen. Da Vinci is designed using a "virtual I/O" software layer and the applications operate independently of the physical I/O. This enables operators to utilize both existing and future I/O platforms without changing the application software. As emerging fieldbus standards are implemented and I/O subsystems are upgraded, the application is unaffected.

Honeywell-Measurex has already sold over 50 Da Vinci systems since the product was launched earlier this year. The latest additions to the Da Vinci family include laser-based, non-contacting caliber measurement, precision basis weight sensors, advanced color change control and wet-end optimization with SpectraFoil as well as new dynamic X,Y and Z sensors. The equipment results in improved product quality and control performance, according to the supplier. With a re-engineered drive system and a Thermal Equalization System, the system is also designed to improve reliability and maintain precise head alignment. Profile measurement in zones as small as 2 mm are possible with the new equipment and full edge visibility at scan rates of 600 mm/sec.

Honeywell-Measurex also recently added an open field solution to its TotalPlant Alcont system. The system's process interface can now be implemented using Alcont's own I/O cards or the interface cards of other suppliers. A fieldbus can be used to distribute the process interfaces into the field within close proximity of the control targets, which cuts down on cabling costs, according to the supplier.

From a distance

As process control advances, manpower at many paper mills is likely to decrease. In future, the remaining operators will need to work on-site less and less as technology enables them to remotely control processes in the paper mill. One such device is the new Field Browser system from Neles Automation. The system allows the operator to monitor smart field instruments for operation status and performance changes from any computer with an intranet or Internet connection. An online connection to valves and instrument products warns the user of any changes via a web page, e-mail or even mobile phone, before processes are disturbed.

The Field Browser works in conjunction with Neles Automation’s new Valve Manager software and monitors each field instrument via a digital HART multiplexer or Foundation Fieldbus. Information is collected and then logged into a HTML document which can be read anywhere via the Internet or using the plant's Local Area Network (LAN). According to the company, the new system allows valves to become "a great deal smarter", while providing increased reliability, speed, and improved performance feedback.

Neles Automation is also launching a Fieldbus version of its ND800 digital positioner called the Fieldbus Smart Positioner. The upgraded version includes an additional microprocessor for more intelligent process control features at the final control element.

The sensitive side

Another area to watch in process control will be development of more online sensors, according to Andre Lemaitre at the Centre Technique du Papier (CTP) in France. "New specific sensors for pulp and paper need to be developed, especially online sensors. There is a lack of online quality measurements," he explained.

In Lemaitre's view, existing online sensors can cope with measuring the more basic paper properties such as moisture, filler levels and basis weight, but more work is needed on the surface properties. "We need more developments into online sensors for measuring physical properties. For example it is very difficult to measure strength online without contact."

CTP has recently developed a new formation sensor, the 2D F-sensor, which gives the floc size distribution by class, the mean floc shape, size and orientation, a periodic mark detection, and the classical formation index. CTP is also carrying out research into pulp sensors, in particular the online measurements of fiber characteristics. "Some online sensors already exist, but we are looking at different measurements, for example fiber flexibility. It is a big challenge to measure this parameter online, but it is important as it is strongly linked to paper properties."

Kaunonen also sees sensors as an important area in terms of process control development. "Advanced analyzers for environmental and wet-end chemistry measurements are being developed. Soft sensors will be used for complex variables, such as printability and runnability. Online paper quality measurements will be considerably faster than today. These quality measurements are embedded into the paper machine structure to avoid open draws," he explains.

Among the latest advances in online sensors is the WebForm system from Messmer Büchel. The equipment is an online web formation monitor designed to analyze the key parameters that affect consistent paper quality. WebForm can detect both random and periodic variations in paper webs over a wide frequency range in the MD (machine direction), and to a lesser extent, in the CD (cross direction).

The high-speed sampling system is usually installed before the size press, calender stack or coater. It has already been tested at a number of UK paper mills producing various paper grades at speeds of over 1,600 m/min. According to the supplier, WebForm can diagnose problematic areas at an early stage and help formulate preventive maintenance programs. The sensor uses a common hardware platform with a series of software modules to enable a range of data analysis and presentation options.

When it comes to testing the process control equipment itself, Tapio Technologies has added a new member to its family of profiling products. According to the company's sales manager Jouko Mäntylä, the TS Profiler is "a little brother for the well known standard tool, the Tapio PMA (Paper Machine Analyzer)." He also says that, "TS profiler uses the same sensors, easier and faster analyzing software and can be upgraded to PMA - and best of all it's cheaper than PMA."

The new TS Profiler uses many of the features included in the Paper Machine Analyzer, which is used to measure CD and MD samples, as well as printed samples. Tapio Technologies offers a complete range of sensors - basis weight, caliper, transmission, gloss, ash, RØ, and the new ultra high resolution Tapio Printability sensor. TS Profiler can use up to four of these sensors at a sample speed of between 0-0.3 m/s. The system's software, WinTapio, operates on two levels - routine operator level with simple and fast displays, and the expert level, which uses more of the advanced PMA features.

Process Control The Precision Platform joins the Da Vinci family

New faces

With more and more suppliers putting their heads together, the pace of development in the process control sector should accelerate as companies take advantage of joint research and technology facilities. It remains to be seen if there are more mergers to come over the next 12 months. But whether PPI's next process control review is littered with the names of newly merged companies or not, the army of experts involved in this field will still be looking forward to making more progress in open architecture systems and online sensors, as well as developing any number of remote devices. And that can only be good news for papermakers as they seek to create higher quality products, ever more efficiently.

Siemens has equipped its Sipart PS2 PA electropneumatic actuator and the Sitrans F flow-rate meter with a Profibus-PA interface. Profibus-PA enables the units to be linked to a process control system. The new design allows the diagnostic scanning of a valve's status, which offers potential cost savings for companies, according to the supplier. The process valve is included in the information exchange between the control system and the pneumatic control valve in the field.

NDC Infrared Engineering has introduced a Windows-based package to be used with its online NIR systems. The system automatically captures and plots measurement data for process analysis and gauge calibration. GaugeView makes trend plotting, calibration setup and checking simpler, quicker and more reliable, according to the supplier.

RKB Opto-Electronics launched the Model 3010 Video Web Inspection Systems to detect quality defects in supercalendering, coating, printing, embossing, laminating and other web manufacturing processes. The systems use a range of high speed 1024 pixel CCD (charge coupled device) line scan video cameras, combined with RKB signal processing technologies for detection of random defects. The company also introduced the Model 2060 Infrared Web Inspection Systems, which expand inspection capabilities beyond basic hole detection capabilities.

Foxboro introduced its first paper machine gauging system - the I/A Series Gauging System. The equipment uses advanced sensor technology from Foxboro's sister company, Eurotherm. For tissue and paper applications, the equipment can measure basis weight and moisture control with a single sensor, as well as providing fault-tolerant measurements.

Pavilion Technologies has released Version 5.0 of its Production Chain Optimization technology suite. The system helps manufacturers to control and optimize all types of continuous processes in a unified software environment. The latest version offers faster application development and deployment through its improved interfaces and refined modeling algorithms, the company claims.

ABB Industrial Systems has launched an automatic health advisory system for paper machines. The ABB Smart Advisor monitors and diagnoses existing or impending process problems and gives operators automatic advice for resolving them. The new online system is an upgrade to the company's AccuRay Smart Diagnostic system.

The company has also developed an online device to measure both sides of the sheet at the same time. The Accuray Smart Fiber Orientation Sensor is designed to combat runnability problems. Based on the laser arc polarization concept, the system uses pulsed infrared laser beams directed at both sides of the sheet. The equipment allows high fiber sensitivity while minimizing interference from fillers, gloss and other surface variables.

Process Control ABB tackles both sides of the sheet

Valmet Automation launched its Sensodec 6S system, which can monitor and analyze the condition of specific machinery components, as well as providing a mill-wide view. Machinery specific functions can be built into the Sensodec 6S system and intelligent multi-channel substation modules can be located near the process. So far, the company has sold some 20 Sensodec 6S online systems. The equipment is based on a high-speed industrial standard TCP/IP network, with independent analysis substations linked to Windows-based user terminals.

Valmet IQ Tension is a full web, non-scan, non-contact and single-sided web tension profile measurement system from Valmet Automation. The system helps to keep the edge roll tension profile within runnability margins and improves the end-product quality. It can be installed on high speed machines in places inaccessible to traditional tension measurement devices, the company claims.

Carotek has upgraded its Event Capturing System (ECS). The system uses ultra-high resolution digital video technology to digitally capture critical process areas. The footage allows mill operators to implement preventative maintenance strategies and can be used with black/white, color or infrared cameras. New features include a Near IR black and white camera which requires little light, a four camera view with no loss of video quality and a redesigned operator interface.

Cerlic Controls introduced a new in-line transmitter CTIL 20/70 to measure consistency and suspended solids in all types of pulp and stock. The stainless steel optical sensor is attached directly onto the process pipe via a welded pipe joint and a clamp coupling. CTIL 20/70 is compatible with all blade sensors and requires little maintenance, according to the Swedish company.

The Microperm 600 Smart is the latest offering from Avatron. The porosity analyzer can be used to measure nonwovens, filter papers, glass fibers and dense sheets. The equipment makes it possible to control the measurement process more accurately and eliminates disturbances such as air leakage, loss of pressure and the effects of excess air being brought in by the web.

VIB has launched a Steam Profiler Plus system which the company claims can offer superior moisture profile control. The unit features a new steam valve that provides direct position feedback to process control computers and displays. The new Positrak valve employs a unique inductive feedback feature on the valve stem to provide direct valve position indication.