Retrieving plant data across all facets of the production environment is vital for optimising productivity and making appropriate business decisions. The challenge is making that data relevant and available to everyone who needs it in the organisation.
Historians provide a means to bring together and store data from a wide range of process control systems. They also historise and archive past data and provide a variety of data retrieval options. Such data allow operations staff to carry out the tasks necessary to optimise productivity levels - for example, comparing different production lines, processes or time frames, identifying adverse conditions that triggered alarms, identifying process deviations, or identifying areas for reducing waste, time, energy consumption or errors.
Accurate insight into plant operations can only be gained from data that provides a complete picture of what is happening so the historian needs to gather all data points from disparate processes, conditions and sources using a common interface between control systems from different suppliers. It also needs to be capable of storing data quickly - particularly if the plant shuts down for some reason and 5000 things happen in a second. Reliability is also vital. If the network goes down and an historian cannot gather data in realtime, it needs to automatically backfill data.
While the plant data provided by an historian is important for plant managers and operations staff, the real value lies in their ability to bring transparency to plant operations across the organisation. However, making the data relevant to the whole business can present a challenge. To date, companies have developed their own systems using proprietary software. The main disadvantage of this approach is, of course, costs arising from the development, time and training for IT staff, and subsequent maintenance of the system. And at the end of the day, the data is still only accessible by a handful of IT specialists in the company.
One solution that has been developed by Citect involves using industry standard technology that eliminates the need for expensive proprietary software and makes plant data accessible to everyone in a familiar and easy-to-use form. The company worked with Microsoft for 18 months to develop a system that uses an embedded Microsoft SQL Server 2005, which is an industry-standard data storage and exchange tool. SQL reports are commonly used because they integrate plant, production and operation data from all areas of the business and present it as meaningful, easy to understand information that can be used throughout the company.
CitectSCADA Reports v4 uses the open OPC standard (object linking and embedding (OLE) for process control) to ensure a common interface between control systems and is capable of accurately recording 100 000 pieces of data per second. While some historians compress the large volumes of data by saving the 'line of best fit' or trend line through data, the Citect system avoids the possibility of clouding the data (by approximating data points) by 'saving data on change' rather than compressing it. To prevent any potential data loss, the system features a backfill mechanism and can connect to redundant HMI/SCADA systems.
With the new standards for alarming there is a lot of focus on improving alarm systems. The Citect system integrates trend and alarm information and provides all the data required for most production and events analysis reporting. Data from the system is accessed in familiar Microsoft Reporting Services formats so the plant manager can view an Excel spreadsheet or pdf and more detailed information can go to the plant floor. Archive trees and plant hierarchies also allow the user to access data at the appropriate level so managers can access summary reports rather than volumes of extensive data. Reports are also available by web to make distribution more convenient.
Using industry standard tools means the total cost of ownership is lower due to reduced development and software costs, reduced installation time, and reduced training and maintenance.
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