Instrumentaton and Control System Blog

The simplest calibration procedure for a linear instrument is the so-called zero-and-span method. The method is as follows:1. Apply the lower-range value stimulus to the instrument, wait for it to stabilize2. Move the \zero" adjustment until the instrument registers accurately at this point3. Apply the upper-range value stimulus to the instrument, wait for it to stabilize4. Move the \span" adjustment until the instrument registers accurately at this point5. Repeat steps 1 through 4 as necessary to achieve good accuracy at both ends of the range An improvement over this crude procedure is to check the instrument's response at several points between the lower- and upper-range values. A common example of this is the so-called -ve-point calib...

The management of alarms is not just about operator displays! The entire system is involved. In some U.S. power plants, alarm systems designed to warn plant operators of abnormal operating  conditions have become overburdened with insignificant alarms. These alarm systems do not provide alarms with proper priorities, and in some cases are not well maintained.  An effective alarm management implementation is dynamic. For this reason, alarm best practices and the application of a continuous improvement rationale are central to this important activity. As alarm systems become less effective, they diminish the effectiveness of all automation.The first step toward an effective alarm management solution is to develop a sound Alarm Management Phil...