The Adroit supervisory control and data acquisition (scada) was the system of choice for Centurion-based systems integrators, SSE, when it replaced the existing legacy system with a world-class one.
The CTMM water provision area stretches from Soshanguve in the north to Rooihuiskraal in the south; and from Atteridgeville in the east to Mamelodi in the west, and includes 30 pump stations. The system used at CTMM took 10 years to develop, three in conjunction with Adroit Technologies to customise the HMI system.
Allan Welfare, SSE managing director, says: “We developed the system from scratch since Tshwane Metro Municipality needed more information on its sites than the previous system was able to provide.
“The change-over was completed three years ago and CTMM has continued to upgrade and expand the system over the last two years to include things such as new reservoirs and meters. Adroit is very scalable, and on the CTMM site we use 2500 to 5000 scan points in total I/O.
“SSE chose Adroit because it is a local product with local support. It is user friendly and easier to configure than many other systems on the market.”
Alarms and support
Over 50 alarm routes where programmed and 35 people incorporated for notification. Using the Adroit Scada’s remote control and monitoring functionality, SSE eliminated the need for a control room and operators. As part of the leasing agreement, SSE offers specialists on standby 24/7 to deal with any hardware problems within a four-hour turnaround. (View nodes exist in the foreman and the engineer’s offices.)
“Scripting for the alarming had to be developed in a special way to handle all the information because of the quantity of alarms on a network this size, and the number of people who have to be notified,” says Welfare. “This configuration saves the client money and dramatically reduces human error. This is particularly important in the monitoring of reservoirs, for example, where, if they run dry, not only does the public go without water, but CTMM experiences millions in revenue losses.”
Incorporated into Adroit 7.0 is the ability to disable alarms remotely. SSE made extensive use of this when designing the CTMM scada alarm system to allow maximum ease-of-use and remote access and control.
The Adroit alarm system is triggered by mains fails, communications fails, level fluctuations within given parameters, pump status and site access; and notifies the relevant parties by SMS.
SSE standard Adroit expressions and visual basic (VB) scripting were used to perform consumption and reservoir volume calculations as well as for some of the alarming functionality. Alarming required special scripting because of the volume of the alarm information that has to be conveyed, as well as the number of people it has to go to – the system has over 50 alarms which it routes to 35 people.
Incorporated into Adroit version 7.0, is the ability to disable alarms remotely to avoid alarm fatigue. This functionality was also used at CTMM to keep alarm information relevant.
Remote monitoring and trending
The out-stations are connected via an MDS brand digital radio system. Data is sent from more than 16 PLCs at the 30 pump stations via remote terminal units (RTUs) and radio to a central station with two Adroit systems. One at CTMM and the other located at SSE, where, as a leased system, SSE handles the system maintenance. Where pump stations do not have RTUs, the PLCs are hardwired and manually operated.
The Adroit system generates trend graphs for all levels, including flows, pump runs, communications failures and battery voltage. The 12 V battery system provides back-up power for the telemetry networks, and is solar-powered at six of the remote sites. Should the power fall below 10,2 V, it automatically switches off for a time span to conserve energy. The four Mamelodi sites have micro-RTUs which report-in every four hours, with a sleep-mode function in between data dispatches to the Adroit Scada.
SSE designed the mimics exactly as they are in the field. This was also a massive undertaking, as following the joining of the municipal councils, accurate information was not available and had to be drawn from scratch. SSE created its own templates for the very complex mimics to ensure accuracy of each site in minute detail including each valve and pipe.
Including a smaller scada system at Rietvlei used to monitor the boreholes; CTMM uses a total of four Adroit HMIs. SSE houses a full functional development system at its head office as part of the lease agreement which serves as an additional back-up for the client. While CTMM also hosts an Adroit Scada at its main office in master/slave configuration for redundancy.
SSE implemented the Adroit Opus reporting tool, which draws information from the scada as well as the IMQS management system into preconfigured reports for CTMM stakeholders. IMQS interfaces with the SEE SQL database and provides information such as flow calculations and water balancing, and is capable of connection to the master station via 3G communication.
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