Automation Industry Association

Challenges placed by Water Distribution Systems

• A typical water distribution system is spread over large geographical area and requires teleprocessing of data from remote area.
• Accurate and reliable data acquisition over telemetry needs reliable and affordable carrier (media) for data like flow, level, pressure, pump status etc. Media for teleprocessing should be easily available and simple in maintenance.
• Communication should be understood by semi- skilled staff who operate at remote places without supervision.

While facing above challenges a favorable factor is that data dynamics is relatively slow in process of water industries. Flow, pressure etc. does not vary fast, except in case of sudden leaks and bursts.

Teleprocessing of data in early 90's was achieved often thru license band radio or via satellite. With the continuous development of automation hardware and software, by early 00's Europe and American water industries started using RTU's based on GPRS/GSM/Broad Band teleprocessing with small application logic built in.

The technology now available for the Indian market in year 2008 is even more advanced, reliable, relevant and optimized. A typical RTU or PLC based system would have:

Communication should be understood by semi-skilled staff who operate at remote places without supervision.

• Local data storage capacity with time stamping capability
• Battery back up in event of power failure
• In built GSM modem or facility to hook up external GSM modem
• Web based navigation for programming and monitoring
• Ethernet Port for Broad band connectivity with relevant features like SNMP, DHCP and Port configuration
• Serial port for fetching data from slave PLC
• System Architecture
• HMI software with schedule dial up OPC server in case of GSM based system
• HMI software with routing and firewall for Broad band based system
• HMI software with remote connectivity for MIS system

As the bulk of data logging occurs at remote places, this data is transferred using GSM channels to centralized control room through periodic data polling or data file transfer over data call generated by pre defined schedule. GSM based systems also have an advantage of sending SMS periodically to various nos. which can be logged. Data sent by this method are time stamped. This fulfills data acquisition needs of the system with accuracy and at low cost. In event of alarm conditions, it is sent out of turn with report of exception. Provision of sending SMS to mobile helps executives to stay in touch directly with system parameters.

In metro or urban areas, where broad band is easily available, broad band and internet based data acquisition make every thing online and real-time based. This is the best form of data acquisition combining accuracy and high speed. When implemented with Google- earth features, geographic positions of pumping station or distribution station can also be embedded for easy viewing of operators. HTML based configuration and programming making it programmable from any where without any geographical limitations. Each RTU becomes a WEB server on its own, emailing reports directly to whosoever needs to read them.

- Niraj Desai