SL-GMS Improves Control Performance
The ECS/OpStation is hosted on a Digital workstation under OpenVMS. The system utilizes a real-time, proprietary database which is continuously communi cating with the plant’s operation through Programmable Logic Controllers (PLCs). The PLCs gather status data into logical groups before sending it, together with analog data, to the database. These units of information, called Motor Status Words (MSW), facilitate real-time communi cations throughout the plant’s control system and advanced dynamic presentations on the ECS/OpStation.
The operator uses the MMI to supervise and control the production facility. The objects on the screen mimic the actual devices on the plant floor, such as hoppers, mill feeds, motors, conveyors and switches, as well as all analog measurements. In addition, text data identifies the devices by name and numerical data presents current
operational statistics. All of the screen displays have been built utilizing the SL-GMS software and as a result change dynamically in real-time to reflect the current state of the process. The display is updated as each MSW and analog data is received by the database. Flashing and color changes in the displays are also used to communicate state data to operators. For example, when a motor is running, the object representing the motor onscreen will be green. The screen object will turn reel and flash to indicate an alarm. Once the operator acknowledges the alarm (using point-ancl click mouse function), the motor objects stop flashing, maintaining a static reel to indicate an acknowledged but pending alarm.
At other stages in production, operators interact with Lhe process by changing set points for a !’ID loop. In this Lyp<: of situation, the operaLor clicks on a dynamic screen object and the MMI pops up :1 template which includes the PII) control mode, the process and the output variables, plu.'i slide bars ancl hutlons to adjust the set point. From the template, the operator also initiates display of trend curves, showing all of the oulput and set points that are related to that PI!) loop. The template is based on SL-GMS and therefore changes in re:d-tirne to ref1ect current conditions and operator actions are transmitted immediately to the control devices.
The intuitive, easy-to-use nature of the MMI results
in improved operator performance and reliability and minimizes the risk of equipment damage and production loss. The multi-tasking X-Window environment reduces the number of control-room operator workstations, cutting the investment withoul sacrificing functionality. Operators open several windows on a single display, each high lighting a different portion of the plant. In a typical example, two main windows are configured as a process overview and a display of the plant's motm systems.
This configuration provides a view of the overall process and each of the subsystems within the process. Older control systems relied on different operator interfaces for each suhsy.-;tem, requiring that opcr,ltors become proficil:nt on several MMJs. Hy integrating all of the plant's subsystems into a common MMI, FLS Auto-mation has significantly reduced the operator training and system maintenance requirements.