PI ControlMonitor
Oversees plant control systems, ensuring accuracy, and keeps a historical system record.
Component Summary
Plant control systems regulate automated manufacturing processes. Generally, these control systems monitor individual unit operations, measuring such variables as Kappa numbers in a pulp and paper plant or brightness in a bleach plant.
PI ControlMonitor ensures that control systems are functioning properly. Each unit operation has a predetermined quality measurement, as well as an acceptable deviation. These parameters, called "control loops," are established in the PI ControlMonitor Configurator. PI ControlMonitor Service continuously reviews control loop statistics and forwards them to the PI ControlMonitor Window in PI ProcessBook. Data are displayed in a ProcessBook screen, where the unit manager, process operator, or instrument technician can check the system's current status. They can also compare it to similar processes at other locations or to historical records.
Technical Overview
PI ControlMonitor displays the quality variable as a dependent variable, and the control loops as independent variables. The display shows a trend (run chart) of the quality variable, as well as a histogram.
ControlMonitor relies on three basic measurements that are part of every control loop:
1. Measured Value
2. Set Point
3. Controller Output
Six types of statistics are calculated for a control loop:
1. Time On Control (TOC): The number of minutes per day the control loop is in the desired mode (e.g., auto, cascade), divided by the total number of minutes per day (1,440), and then converted to a percentage value.
2. Average Controller Output: The average value for controller output for the time period (one day, for example).
3. Stability: The measurement of how the loop is tracking a set point. If the loop is unstable and cycling with large amplitudes, this number is close to 0 percent, and the loop is considered poorly tuned. If the loop is stable, the number is close to 100 percent.
4. Average Absolute Error: The average deviation from set point over the time period being displayed.
5. Standard Error: A unitless measurement of error calculated by dividing the Average Absolute Error by the average target.
6. Point Count: A unitless number that correlates to performance of a control loop. The point value is calculated by adding the point values of the Time On Control, Average Controller Output, Stability, Standard Error, and Average Absolute Error.
System Requirements
- Windows NT with Service Pack 3 or higher
- PI ProcessBook 2.0 or higher
Component Summary
Plant control systems regulate automated manufacturing processes. Generally, these control systems monitor individual unit operations, measuring such variables as Kappa numbers in a pulp and paper plant or brightness in a bleach plant.
PI ControlMonitor ensures that control systems are functioning properly. Each unit operation has a predetermined quality measurement, as well as an acceptable deviation. These parameters, called "control loops," are established in the PI ControlMonitor Configurator. PI ControlMonitor Service continuously reviews control loop statistics and forwards them to the PI ControlMonitor Window in PI ProcessBook. Data are displayed in a ProcessBook screen, where the unit manager, process operator, or instrument technician can check the system's current status. They can also compare it to similar processes at other locations or to historical records.
Technical Overview
PI ControlMonitor displays the quality variable as a dependent variable, and the control loops as independent variables. The display shows a trend (run chart) of the quality variable, as well as a histogram.
ControlMonitor relies on three basic measurements that are part of every control loop:
1. Measured Value
2. Set Point
3. Controller Output
Six types of statistics are calculated for a control loop:
1. Time On Control (TOC): The number of minutes per day the control loop is in the desired mode (e.g., auto, cascade), divided by the total number of minutes per day (1,440), and then converted to a percentage value.
2. Average Controller Output: The average value for controller output for the time period (one day, for example).
3. Stability: The measurement of how the loop is tracking a set point. If the loop is unstable and cycling with large amplitudes, this number is close to 0 percent, and the loop is considered poorly tuned. If the loop is stable, the number is close to 100 percent.
4. Average Absolute Error: The average deviation from set point over the time period being displayed.
5. Standard Error: A unitless measurement of error calculated by dividing the Average Absolute Error by the average target.
6. Point Count: A unitless number that correlates to performance of a control loop. The point value is calculated by adding the point values of the Time On Control, Average Controller Output, Stability, Standard Error, and Average Absolute Error.
System Requirements
- Windows NT with Service Pack 3 or higher
- PI ProcessBook 2.0 or higher