by Mark Halliwell, Taggle Systems
SCADA (Supervisory Control and Data Acquisition) Systems are a major contributor to the daily operation of most water service providers’ activities. A wide variety of sensors connected to RTUs (Remote Telemetry Units) or PLCs (Programmable Logic Controllers) collect data from, and allow control of, equipment located throughout the water supply system, from the point of raw water capture through to service reservoirs and sometimes beyond.
SCADA operators can never have enough useful data but there are some limiting factors on how many, and where, sensors are installed. Chief amongst these is the cost of the communications media required to get the data into the SCADA system and the cost of providing a suitable power supply for the sensor and associated communications hardware.
In the past, telephone lines were used extensively but these were expensive and susceptible to lightning strikes and the effects of moisture that played havoc with reliability. Point-to-point data radios using licensed spectrum and 3G modems came along and made many of these communication challenges much easier to overcome.
A downside, however, was the associated costs. Setting up a sensor, RTU and dataradio or 3G modem requires a sizeable power supply which can only be met by having a permanent 240VAC supply, a battery-backed solar powered setup or, in extreme cases, a battery-powered site that requires a site visit every few months to replace batteries.
The economic burden of these costs has limited the number of devices that could be deployed, leaving operators without much of the context that would make their interpretation of operational situations so much easier.
New possibilities thanks to LPWANs
The advent of Low Power Wide Area Networks (LPWANs) is presenting SCADA managers with opportunities to rethink their data needs and explore the possibility of acquiring data from many aspects of their water and wastewater management systems that previously were beyond economic reach.
Battery-powered sensors providing regular updates over years of maintenance-free field life are now a reality. Sensors with low-cost communications can now be viewed as “fire and forget”, to be visited only when there is a site issue or the sensor is to be moved to a new location.
Take, for example, a simple rain gauge. A good quality rain gauge costing $800-$1200 generally requires equipment and installation costs of an additional $5000-$10,000 to collect its data remotely. With a Low Power Wide Area Network in place and battery-powered transmitters capable of providing hourly updates for ten years or more available for about $200-$250, including ten years data delivery, the overall cost is greatly reduced.
These lower costs now make it possible to deploy many more rain gauges, providing far greater context around rainfall, water consumption habits, the effects on inflow and infiltration on wastewater networks and more.
Being able to determine if a pipe is being affected by inflow or infiltration through correlation of sewer levels with rainfall data can save many thousands of dollars in testing costs.
But what about other sensors? Having generic transmitters suitable for use with industry standard outputs (discrete, pulse, analog 0-10v, 4-20mA etc as well as serial protocols such as Modbus and SDI-12) means Taggle’s LPWAN can offer data acquisition for many sensors already used by Australia’s local councils and water utilities. Pressure, sewer overflow, level and flow are just a few of the sensors that can be deployed to present a more detailed picture of what’s going on.
Are you worried about getting the data into your SCADA system? No problem, Taggle provides data in a range of formats, including CSV, MQTT, JSON, DNP3 and others.
With low-cost communications and no need for expensive on-site power installations, more sensors can be deployed more widely and more cost effectively than ever before, making the concept of SCADA everywhere a reality.
This partner content is brought to you by Taggle Systems. For more information, visit www.taggle.com.au.