Feb
25
One of the most obvious reasons for poor control utilization is a broken or unreliable transmitter or sensor. As addressed in Chapter 3 of Advanced Control Foundation – Tools, Techniques, and Applications, if the control system is designed to be consistent with the international function block standard, IEC 61804, the status attribute is always communicated …
Feb
11
It can be shocking to examine control utilization in a plant where performance tools have not been installed and/or not used. For example, in the mid-1980s a control survey was conducted at a major pulp and paper plant where the control system had recently been updated to the latest distributed control system. At that time …
Feb
04
A plant operator is usually responsible for managing one or more process areas, with (potentially) hundreds of control loops and process measurements in each area. The operator’s job is made easier if the control loops in these process areas are in automatic mode and can compensate automatically for disturbances and maintain the operating conditions the …
Jul
30
Courses required for an engineering degree are designed to provide the student with a sound technical foundation for work in industry. However, in most cases these courses do not address the terminology and common practices that an engineer must know to design, implement, checkout and commission a process control system. Universities can help bridge this …
Jul
02
As the ISA50 function block team considered how to improve plant operations through a more comprehensive implementation of mode in the control system, they realized it would be important that the control blocks, such as the PID, be designed to automatically take into account up-steam and downstream conditions that impact control operation. Thus, inputs and …
Jul
11
The method used to process analog inputs and outputs is unique to each control system. Also, controller and IO bus design influence how often measurement and outputs are updated and thus dictate the control execution rate that is supported by the control system. Understanding the limitations imposed by the basic control system design (i.e., controller …
