WATER METER MONITORING AND LEAK DETECTION

AMR

AMR or Automated Meter Reading is the term given to the connection of a logger or remote telemetry unit to a water meter. The information obtained may be used for a number of different purposes: billing, consumption profiling, network planning and leak detection.

BILLING

Consumption figures have traditionally been obtained by a meter reader who visits the site at pre-determined intervals to read the dials on the meter. Connection of a telemetry unit allows readings to be automatically transmitted to the water supplier. Rather than a single reading at the end of the billing period, utilities can profile consumption at shorter intervals such as a day.
 

LEAK DETECTION

Water use will follow a typical pattern for most users. In a domestic application, consumption will peak early in the day and again in the evening, falling off to very low figures overnight. If a threshold is set on the night time consumption, alarms can be raised if a leak causes consumption to rise. Rather than being applied at a household level, leak detection is usually applied at an aggregate level for example on a supply main feeding a couple of hundred households.
 

In rural applications, water may be used to fill stock troughs or tanks. The flow in these situations rarely goes outside of a predictable range. A sudden high flow indicates a pipe burst or leak. With  the potential for leaks to go un-noticed for long periods of time, a leak can become very expensive. Installing a telemetry unit on the water meter thus provides a cost effective early warning alarm.

METER CONNECTION

One of the most cost effective sensor outputs is the pulse output. A pulse sensor provides a closed contact when a specific event occurs: for a flow meter, this will be after a known quantity of flow occurs.. When choosing a meter and pulse head, users can choose an output rate which will give pulses at a rate which can be easily counted by the telemetry unit e.g.. 1 pulse per 1l, 10l, 100l, 1kl, 10kl, 100kl. The telemetry unit then counts the number of pulses which occur in the chosen logging interval (e.g. 15 min, 1 hour, 1 day). For compatibility with the mechanical indicators typically fitted to flow meters, telemetry units also allow users to create a flow totaliser. This can be set to a start value which matches the meter dials and , as flow accumulates, will always agree with the mechanical indicator.
 

NON URBAN METERING

In many jurisdictions, attention is turning to installation of telemetry on water meters for regulatory purposes. This may be for both billing and resource management. Under the Water Act, jurisdictions who collect water use data electronically must provide it to the Bureau of Meteorology for incorporation in to the National Water Accounts. Fitting telemetry to water meters makes this task very simple.
Although, as shown above interfacing to meters is not an onerous task, requirements to provide security over the captured data and to prevent tampering may require additional elements to be added. For example, the NSW “Data logging and telemetry specifications” published in 2019 call for telemetry units for non urban metering to include:

- fitting tamper evident seals on the meter housing.
housing using screws with security heads on the telemetry unit enclosure to prevent it from being opened.
- fitting a tamper switch to the enclosure to detect when it has been opened.
- including a detection lop in the meter cable to alert if the cable is cut or damage.
In addition to this, some jurisdictions require that the telemetry units send the captured data in a specific format format  to their data hosting platform.
The YDOC ML417  is one  of only a small number of devices capable of meeting these requirements. It is available with a number of different power supply options: single use lithium batteries, solar power and rechargeable batteries or external power.
With the YDOC unit you will also have no problems connecting to the range of Pattern Approved flow meters: all of these offer either a Pulse, SDI-12 or MODBUS/RS485 output, which can be connected directly to the ML417 united.
To purchase a NSW Water / DPIE approved LID for closed pipe metering, contact Pacific Data Systems on 07 3361 2000  or visit their web site: Pacific Data Systems

YDOC METERING RTU

 YDOC’s MLN417DS-LI telemetry unit is ideally suited for flow metering. It is powered via a single use Lithium battery (13AH) and features three pulse channels. As the unit also carries a serial input, it may be connected to a wide range of SDI-12 and MODBUS meters. Most modern domestic and rural water meters now include an inbuilt metering device. A small battery powered head (the Cyble) can be fitted on top of the meter and will give a pulse output each time a nominated amount of water  flows through the meter.
High and Low flow alarms can be set up in the RTU and alarms notified by user via SMS or Email. The readings are stored on the RTUs on board memory card and are also transmitted to a YDOC Insights server where they can be viewed on any web connected device.
 

LoRaWAN

The LoRaWAN protocol offers the chance to completely change the market for automated meter monitoring. Once a LoRaWAN network is deployed in an area (which is as simple as someone installing a LoRaWAN Gateway)  LoRaWAN nodes can be added at any meter site. Because data from meters is only required at infrequent intervals (e.g., once a day)  the nodes will last many years on a single use lithium battery. This allows hardware designers to dramatically reduce the node cost and makes for very simple installation. An AMR version of the Tekbox TBS12 is under development .
The TBS12PC is the ideal device for LoRa WAN based meter reading. It has two pulse inputs and outputs two values: the flow for  the period and a flow totaliser - which can be initialised with the same value as on the meter’s mechanical indicator so the two will then remain in lock-step.