SCADA package provides range of capability
When examining requirements for personal computer-based supervisory systems, users should consider several levels of functionality. These include a graphical operator interface, trending capability (real time and historical), report generation capability, the dynamic links to other software packages through Dynamic Data Exchange, data archival capability, statistical analysis, and the ex...
When examining requirements for personal computer-based supervisory systems, users should consider several levels of functionality. These include a graphical operator interface, trending capability (real time and historical), report generation capability, the dynamic links to other software packages through Dynamic Data Exchange, data archival capability, statistical analysis, and the existence of supervisory control functions.
The need to collect and display data is only part of the application requirement for many systems. Operators should be allowed to see and act upon the state of the system. The supervisory station must also have the capability to analyze and/or react to data being collected from many processes.
Planning the design
When designing a solution for systems that require functions across this range of requirements, the designer may select either a comprehensive package or use multiple packages. When using multiple packages, users must integrate the tools and then support them over the long term.
CiTect5 from Ci Technologies Inc. (world headquarters in Pymble, NSW, Australia and also located in Charlotte, N.C.) is a supervisory control and data acquisition (SCADA) package that addresses requirements across the range of needs listed above. While providing the graphical display capabilities standard with human-machine interface (HMI) software packages, it also provides sophisticated trending options, including a range of statistical process control (SPC) options.
The HMI module functions as a typical Microsoft Windows-based package with graphical representations of the application, including pumps, valves, pipes, agitators, etc. This also includes the ability to display loop faceplates and numerical data within the graphical environment. The most important advantage is the trending options that come standard with this package. These include the routine ability to trend not only individual and multiple points but also the capability to examine data easily, in as much detail as required. Though comprehensive in scope and ability, the only shortcoming of the package's multi-point trend display is that all pen identification is not displayed. Users must select the pen color button to see the associated tag name.
Beyond the typical trend functions, though, is a set of SPC functions including x-bar, R-bar, standard deviation, Cp and Cpk, Pareto, and xy charts. These functions can be assigned to any tag and are fully configurable for sample size, sample rate, and control limits.
Dreaming of 'genie'
Configuration of this package is aided by the selection of standard icons and functions. These include a comprehensive library of tanks, pumps, and valves along with packaged functions that CiTect refers to as "genies" for features such as loop faceplates. In addition to the standard library, users are given the tools to create custom objects and "genies" as required.
Configuration of any page within an application begins with selection of a page template from which the prebuilt trend and SPC templates are available. This allows the user simply to enter the desired tag names and initial parameters needed to define the SPC operation.
This review was based upon version 5.0 of CiTect running under Microsoft Windows 95. Version 5.2 is currently available.
For more information on CiTect5, visit www.controleng.com/freeinfo
Contributing Editor, Tracy J. Coates P.E. is a consulting engineer at PCE Engineering, Johnson City, Tenn.