New technologies and applications
Suite spot30 September 2004
Yokogawa's new AAASuite is a bolt-on alarm management system for optimising process alarms issued by control systems. Its job is to select only those alarms considered necessary, to help prevent alarm ‘flooding’ and promote safe and cost-effective plant operations. It automatically detects typical nuisance alarms – such as repeating high/low alarms caused by improper alarm settings and chattering high/low alarms caused by improper PID parameter settings – and notifies both the alarm cause and the required corrective measures to operators.
AAASuite can store the optimal alarm settings and automatically download the required settings to the control system when a plant startup, plant shutdown, product grade changeover, or process load change occurs. And when operators are allowed to change alarm settings during plant operation, the new settings are automatically uploaded to the AAASuite database the next time there is a change in the operating conditions.
The program automatically prevents the repetition of nuisance alarms that are detected through the detection and diagnosis functions, utilising the control system’s functions. When the process status changes in such a way that unnecessary alarms no longer occur, it automatically lifts this alarm suppression. The system automatically generates additional alarms including the periodic re-notification of longstanding high/low alarms caused by unstable plant situations and the predictive alert of critical alarms that can trigger an interlock sequence.
AAASuite is intended to provide a monitoring function to meet the increasing problems encountered in industrial plants that have been aggressively streamlining their control rooms and control systems, reducing the number of operators to achieve more efficient operations and improve their prospects for survival against harsh global competition.
Ideally, alarms should be systematically and uniformly distributed at the transition points between normal, error, and shutdown plant status so that operators are notified only when and as necessary. In conventional control rooms, operations have tended to rely on the presence of personnel, including some with special expertise, to monitor and assess a situation in which alarms generally occur randomly. If such control rooms and control systems are realigned without proper corrective measures, even a minor variation in process status can immediately trigger numerous alarms.