ScadaBase is a graphically enhanced SCADA software package designed to take advantage of the robust, multiuser multiprocessing and networking facilities of the Linux operating system running on Intel-compatible computers. The software’s event-driven processing mechanism offers a high degree of scalability. ScadaBase can be configured to operate as a small, monolithic SCADA system with a few hundred I/O points, or it can be run among several computers across a TCP/IP network as a large distributed control system with thousands of I/O points. ScadaBase is a full-featured SCADA software package for the Linux operating system. The software’s modular architecture lets you configure the system for a variety of industrial monitoring and control applications. Because ScadaBase conforms to industry standards, you can easily extend and customize it for integration with existing instrumentation and information technology infrastructures. The software includes an impressive set of data management features, including the Historical DataBase (HDB), the Real-Time DataBase (RTDB), and the Message DataBase (MDB).
ScadaBase offers peer-to-peer communications, allowing several systems to control separate areas of a process yet share common variables across a network as if they were local (see Figure 1 ). For redundant configurations, hot standby systems with auto-failover are also supported. With exception-based communications facilities, the software supports a large number of local or remote HMI operator consoles. HMI screens can be displayed on X Terminals, PCs running X emulation, or other Linux systems. For example, ScadaBase running with Virtual Network Client software allows you to look at data and control processes via Netscape.
With the software, you can scan external data periodically, poll it on demand, or receive data on an exception basis. ScadaBase can time-stamp input samples with 1 ms accuracy and handle after-the-fact processing of high-speed acquisitions and data uploaded from RTUs with time stamps. The software allows concurrent support of devices ranging from PLCs, RTUs, loop controllers, or plug-in boards. Distributing I/O among networked platforms that serve as front-end processors supports high-speed DA rates, redundant I/O, and load balancing. With ScadaBase, you can write custom I/O interface modules using the I/O toolkit.
The software lets you monitor I/O devices, process alarms, generate reports, display real-time and historical trend data, and perform math- and logic-based processing. Data are collected and processed according to system configuration parameters and sent to the appropriate devices or computer systems. ScadaBase supports application-specific programs, and multiple users can work in the multitasking environment concurrently and exchange data with external software products (e.g., spreadsheets, relational databases, and statistical quality control packages).
ScadaBase’s Real-Time DataBase (RTDB) directs the acquisition and processing of all information. The RTDB determines how often data points are acquired and processed, how to convert analog values into engineering units, and how alarm limits and other processing tasks are handled. Acquired data can be validated, filtered, converted, processed, and alarm-checked according to criteria you select for each data point.
The Run-Time Subsystem provides control and synchronization of such system activities as processing real-time variables; handling message I/O, timers, control outputs, and report-by-exception events; checking alarms; and monitoring system performance. Real-time process variables are subject to preprocessing operations, such as calculations, RTD linearization, and thermocouple or engineering unit conversion. Data received from intelligent devices may not require further processing, and they may simply be stored in the RTDB. Alarm checking with three high/low limits, rate-of-change thresholds, deadband filters, and alarm inhibits are provided. Startup values, filter factors, set-point operations, control calculations, and postprocessing operations are also configurable through the subsystem.
ScadaBase’s Display Builder lets you create operator screens that graphically depict the monitored process using tools that generate text and draw lines, circles, ellipses, arcs, splines, polygons, and boxes. Regular and isometric grids; X,Y coordinate positioning; and conversion tools assist in the design of screen displays.
Text fields, objects, and symbols can link to the RTDB. You can use text fields to display or input information in integer, float, or string formats. Operators can use bitmapped images as backgrounds, objects, or as fill styles. And you can import AutoCad DXF files, preserving the images vectors, blocks, and attributes.
ScadaBase comprehensive alarm features let you create custom alarm strategies. These features come in the form of pre-engineered applications, toolkits, and action interfaces. When a processed data point results in an alarm condition, the subsystem generates an alarm data event and a separate message event. The software maintains the alarm data state in the RTDB and in the alarm queue. Message events are simply alarm messages written to the Message DataBase. You can view or log these messages using several different mechanisms.
This subsystem provides access to multiple compression algorithms and history files. Working in this part of the program, you can extract historical data from the Historical DataBase (HDB) and transfer the information to flat files or comma-delimited files for input into spreadsheets for analysis and reports. The subsystem logs real-time data in the HDB and is configured for the number of I/O points that it may contain.
The Run-Time Configurator is a graphically enhanced, menu-driven software module for system setup, maintenance, and administration. Intuitive in operation, the configurator uses pop-up windows, pull-down menus, buttons, selection lists, and text entry fields. You define the processing functions of ScadaBase online via tunable parameters, which can be altered while the system is in operation. ScadaBase allows quick and easy configuration of the RTDB, graphical displays, reports, math and logic functions, and access to user-defined applications.
Graphical trending package provides trend data collection, retrieval, plotting, and reporting for real-time or historical data. Hard copies of trend plots can be generated by printers and plotters.
Trend data are collected as new process variable digital input, and state variable information is measured or calculated in ScadaBase. Parameters involved in trending display requests (e.g., background and grid color, pen color, line width, line style, marker style, grid on/off, time span [X axis], and value span [Y axis]) are configurable.
ScadaBase provides software modules for management of information access by relational databases. This provides an on-change gateway between a ScadaBase system and relational databases. External database applications can send data to ScadaBase, which readily interfaces with Microsoft applications using TCL/TK, SQL/ODBC, and Samba.