b'MEASUREMENT AND CONTROLsets of CD actuators simultaneously, taking into account interactions between different inputs and outputs and their constraints. The ultimate goal is to produce a sheet where all profiles (e.g. weight, moisture, caliper, etc.) are uniform. Multivariable MD control can be used to minimise the future predicted variation of process variables while honoring their quality and physical constraints. In addition, it can be used to execute automatic grade change control in open or closed loop manner. The controls coordinate the corrective actions of multiple CD actuators and extend their effective control range. They take into account the relationships and cross-coupling that exist between different CD actuators and help in understanding associated constraints and limits.Figure 3. Honeywell ProFlow II Actuator showing dilution water piping entering the headbox.To sustain a high level of control performance, mill operators utilise solutions such as adaptive alignment,high-resolution CD profile controlAccurate sensor measurements, which performs online monitoring of CDwith intelligent actuators, and acoupled robust MD and CD controls, profiles to detect any quality problems.comprehensive portfolio of qualityoptimises control of papermaking The correction can be fully automated orcontrol applications. operations to provide continuous require operator approval. All detection,product quality and quick recovery identification and deployment is doneThe combination of fast respondingfrom process upsets. Energy savings while the CD controls are in operation. sensors and a fast QCS scanningand production increases can also platform enables the highest level ofbe realised through the elimination of Papermakers require increasinglyperformanceresulting in up to 65control range limitations.automated controls to compensatepercent faster control response.for the loss of operator experienceSUMMARY The due to retirement, consolidation, andThe specific benefits of HoneywellsThanks to ongoing technologycombination curtailmentsend-to-end solution include: advancements, pulp & paperof fast companies can automate qualityresponding REALIZE KEY OPERATIONAL BENEFITS Improved control of processcontrol and implement more consistentsensors and As production rates rise, often stretchingvariability and precise measurement capabilitiesa fast QCS the design capacity of paper machines,Greater operational consistency as part of their papermakingscanning Honeywells QCS solutionfullyIncreased overall productivity operations. These improvementsplatform integrated with its Experion DistributedFewer sheet breaks deliver key benefits by increasingenables Control System (DCS)offers fastLower energy consumption production speed and yield, which, inthe highest scanning and processing speeds,Less scrap materials turn, enables increased productivitylevel of precision measurement technology,Increased product value and profits. performance58 WORLD PULP&PAPER'