Battery powered utility water meters

Flow Measurement & Control

October 2007 Flow Measurement & Control

In a large consumer meter environment, monitoring both flow and pressure and alarming on these two variables, can significantly contribute to water demand management, water balancing, as well as managing the risk associated with high pressure water bursts.

Supervisory and Control Expertise won a contract to supply a battery driven, flow and pressure monitoring and alarming system for mainly mechanical water meters for Rand Water. Due to where water meters are normally located, line of sight for radio and cellular signal strength cannot be guaranteed. More than 200 of these devices were successfully installed, using cellular technology, and the system has been running for nearly a year.

From experience we knew that GSM-SMS communication works more effectively than GPRS in low signal strength areas, and we opted to activate only the SMS communication on our cellular device. The system was installed over the total supply area of Rand Water, and there is not a single site that is not reporting (though some have pretty weak signals <10% of full strength)

The units installed in the field are called SMãR-FP-units, and stand for (SMS monitoring and alarming remote unit - for flow and pressure). These units are IP68 rated, and can have external or internal antennas for operation in submerged conditions.

Figure 1. The SMãR-FP-unit installed for monitoring and alarming on flow and pressure

Monitoring functions

* Can be remotely configured to record flow volume and pressure at between 5 and 60 minute intervals.

* Units can be synchronised to the reading on the flow meter.

* When the buffer is full, the recorder data is sent to a server computer, where it is made available in both OPC and written into an SQL-type database for trending and reporting.

* An option for advanced graphing like statistics, summation, etc, is available for analysis.

Alarming functions

* High, low and sudden change alarms for pressure are generated in intervals of 1 minute, and alarms immediately sent to the central server for action.

* High, low and sudden change alarms for flow are also generated.

* Tamper alarm on trying to remove the box is generated at any time.

Figure 2. The SWãSH-server interaction with other systems

Server functionality

To manage all the information and distribute alarms and facilitate interfacing to other systems, the SWaSH-server has the following functions:

* Capturing data from the SMaR-FP-units.

* Sending SMSs for alarming purposes to pre-configured addresses.

* Storing and making available data and information.

* Insert trend and alarm information into Industrial SQL database.

* Configuration of parameters for monitoring and alarming functions.

* Hosting an OPC Server (DA versions 1, 2 and 3 compliant) for access to current data and alarms. This is a two-way interface which allows configuration of certain operational parameters as well as acknowledging of alarms from for instance a scada environment.

Figure 3. Example graphs with flow and pressure information for the same reservoir for four weeks

Typical information from the system

Each meter has a status screen with last meter reading, flow, pressure as well as alarms. Shown above is a typical 4-week graph for pressure and flow for reservoir.

For more information contact Jaco Hoogenboezem, Supervisory and Control Expertise, +27 (0)16 982 3700, [email protected], www.sce.co.za

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Flow Measurement & Control

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