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New South Wales - Non Urban Metering |
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| NSW Non Urban Metering Project | In New South Wales, the extraction of water for irrigation is controlled by the Department of Industry and Environment, through Water NSW. The whole process is undergoing change to ensure the process is managed in a sustainable fashion which is in turn fair for all water users. In line with the National Water Plan, all water taken for irrigation must be monitored. NSW Water collect the data from on farm meters and aggregate it up to gain a picture for what is happening across a region or catchment. TOIP’s YDOC-NUM Local Intelligence Device (LID) is available as a Primary or Secondary measurement device. | |||
| Flow Meters | The amount of water taken for irrigation via closed pipes can be measured accurately and economically using any of a wide range of flow meters. Traditional flow meters were fitted with a mechanical dial which showed the accumulated flow. The simplest electronic interface for such meters is a reed switch: a magnet on the dial for the base units (e.g. 100l) passes the reed switch once every revolution, giving a temporary short or pulse on the output of the switch. Newer units use electronic counters with a digital display and use a transistor circuit to provide the output. Pulse output meters are cheap to build and very simple to log. The device which connects to the meter needs a miunimal of circuitry to read the reed switch and count the number of flow pulses. It is standard practice in metering to maintain a flow totaliser - an electronic equivalent to the mechanical wheels - and to send this value rather than the number of pulses recorded in the logging period. This ensures that if a reading is missed, no data is lost: the totaliser will always hold the latest total and the flow for individual periods can be obtained by subtracting the starting totaliser value form the end totaliser value. |
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| MODBUS METERS | There are also a number of more complex digital flow meters on the market. Although most can produce a pulse output, their primary benefit is in being able to capture more detailed information on the flow, such as maximum, minimum and average flow rates. The disadvantage of the digital meters is that they must be powered. Although digital meters are available with both MODBUS and SDI-12 interfaces, only MODBUS meters are currently approved under the NSW non-urban metering framework. | |||
| Local Intelligence Device (LID) | The term Local Intelligence Device (or LID) is given to the device which conencts to the meter, logs the readings and transmits them to a remote server - in this case NSW Water's Digital Acquisition Service or DAS. An LID is more commonly known as a Remote Telemetry Units or RTU. This unit will have its own power supply to drive the sensor, have electronics to read the sensor and memory to store the readings taken over time. It will then have some communications which is capable of sending the data to a remote computer system for analysis and display. The most common - and most useful - method for data transmission is to send the data over the mobile telephone network. |
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| YDOC-NUM | The YDOC-NUM has been designed to meet the requirements for an LID for non urban metering. It is powered from a set of 3 D-sized alkaline batteries. This gives a life span of 10 years and ensures replacement cells are cheap and readily available. The YDOC-NUM is setup for wall or enclosure mounting and a post mounting bracket is available. It comes with an internal cellular/mobile phone antenna but an external high gain antenna is available for use on sites with poor signal strength. The YDOC-NUM enclosure incorporates a tamper switch which triggers when the lid is opened and supports a Cable Cut detection loop, which will trigger an alarm if the meter cable is cut. Follow this link to download the YDOC-NUM brochure and contact a registered DQP to arrange supply of a unit. |
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