HVAC Control in the New Millennium.pdf - HVAC.Amickracing

Heat, Ventilation and Damper Control Trendsintegration, better communications, more intelligence in the equipment,increased use of PCs and improved price/performance ratios.Motion Control IntegrationIntegration of motion control systems and the information thatthey control in future automated control systems will make this technologymore useful, less complex, more powerful, and physically smaller.As the machine adapts to use fewer and smaller components, new formsof actuators will be adopted.Smarter and smaller electronics will allow multi-box solutions tobecome single-box solutions with the electronics built into the motor.With the trend towards more open controls, the drive intelligence will beintegrated further into the motion control module.The first step is the integration of the control with the amplifier.Intelligent drives will replace power blocks and traditional amplifiers.An intelligent drive contains the traditional amplifier along with featureslike auto tuning, auto tuning on the fly, diagnostics, horsepowercalculation, calculation of the three main torques being delivered (frictiontorque, acceleration torque, and work torque), feedback of position,velocity, acceleration and inertia calculation. Once you know accelerationtorque and acceleration rate, inertia can be calculated.There are already products that can do closed-loop control with ahybrid step motor. In the future, motion control platforms will allow anymotor type to be controlled for a wide range of velocity and positioningapplications. The feedback device may be an encoder, resolver or tachometerwhich will be electronically recognized and controlled to providethe needed feedback signals. Many motion applications will usesensorless positioning techniques where embedded signals from themotor itself provide the feedback signals.Contrex has a line of position control products designed to addintelligent control and operator interface to all types of variable speeddrives. This makes it possible to register and synchronize independentmachines, allowing them to work together and to followpreprogrammed motion profiles. Rockwell Automation has added enhancedmotion control in their Allen-Bradley ProcessLogix distributedprocess control system.©2001 by The Fairmont Press, Inc. All rights reserved.