RTU innovation promotes greater flexibility

24Jul

With modern telecommunications revolutionising the water industry, remote telemetry has become an incredibly powerful tool. Like all industries, data is king. If you have a handle on the who, what, where, when, why and how much, you can gain incredible efficiencies and significantly enhance operational performance.

Remote telemetry is not new, but it is only relatively recently that it has been really exploited by some of the forward-thinking water companies. With such geographically dispersed assets and raw materials – in the form of water in its various clean/dirty guises – water companies really have their work cut out in terms of controlling these assets efficiently and within set parameters.

Chris Fryatt, Senior Engineer at Metasphere elaborates: "This is where remote telemetry units (RTUs) come into their own. With autonomous technology that can be left out in the field, providing up to date and pertinent data, water companies now have a much better idea of the bigger picture. This helps them to gain efficiencies, reduce wastage and save costs in many different ways.

RTU devices have changed considerably as the electronics inside them has advanced, but their data capturing, gathering and disseminating role still remains primarily the same. What companies like Metasphere are now offering – using direct input from the water companies – are even more robust units that offer greater functionality without any noticeable increase in complexity. Indeed, it can be argued that the company's new Point Orange unit is even easier to use than the model it replaces, while offering performance and features far above its predecessor.

"Primary users for these types of RTUs are the water and sewerage (WASC) companies," Fryatt explains, "with typical applications including pressure and flow monitoring and combined sewer overflow (CSO)." Point Orange provides real-time remote monitoring of up to five sensors and has software programmable I/O functionality for hundreds of configurable combinations and includes support for analogue, digital and counter inputs. The multiple configuration options include local monitoring of battery voltage, GPRS signal strength and ambient temperature.

Although the unit can offer real-time data sharing capabilities, a feature that some water companies exploit, some users only want data once a day or once a week – with a data centre managing alerts. However, they do still rely on the built-in intelligence within the RTU to alert them to any anomalies. The trade off in these instances is battery life, with regular use sapping the battery power more rapidly.

It is in regards to battery life that one of Point Orange's unique features comes in to play, a feature developed by Metasphere to cater for some of the more demanding applications within the water industry. "If you are using the RTU, with an external battery pack in a role that involves lots of activity then it is a given that the battery will not last forever," Fryatt explains. "When the Point Orange is powered by an external battery pack, upon expiration of this pack, the RTU will automatically switch to its internal battery pack. This event can be captured and reported to the data centre, alerting the depletion of the external battery pack. When the old external battery pack is replaced, the RTU automatically reverts back to the external battery pack to preserve the energy of the internal pack. "Throughout this, the Point Orange doesn’t reset and continues to operate and collect data," he continues. "Normally, when the battery depletes, the RTU can no longer function, resulting in loss of site monitoring between battery replacements.

The use of modern lithium battery packs offers high energy density; however, detecting end of life can be difficult due to the sharp voltage drop. With Point Orange, this problem is bypassed as it makes provision for an extended overlap period, the internal battery pack alone can offer up to five years' battery life. We are also developing internal algorithms to monitor the battery usage. This, coupled with data collected using the internal temperature sensor we are able to estimate a percentage of capacity used.

With ease of use being high on the water industry’s priority list, Metasphere has developed (and patented) software configurable I/O: "With our previous product, configuring different I/O modes was done manually. Similarly, in the past, specific applications required either factory settings or different products," Fryatt explains. "This unit can do all this via software by switching signals within the hardware. The advantage of this is you can have the same RTU with the same connectors, but it can be configured for different applications. It eliminates the need for bespoke product sets by offering a single solution. "We have also developed a unique immersion sensor," Fryatt continues. "To monitor flooding, you would normally use an external float-switch, which can get stuck or ragged up. We have got around this dependency on external mechanical switches by developing and patenting an internal sensor that allows the RTU to detect if it is underwater. There is an internal non-contact sensor, which is queried regularly to determine if the unit is submerged."

The growing popularity of WITS (Water Industry Telemetry Standards) has led to the recent launch of Metasphere’s WITS enabled outstation, the MM-IM. This capability will be extended to the Point Orange. "Although WITS is the future," Fryatt concludes, "it is still important to cater for different masters. For this reason the Point Orange unit is compatible with protocols such as Medina, DNP3 and WITS DNP3. There are plans to add support for FTP (File Transfer Protocol) data transfer. An intrinsically safe ATEX certified version, named Point Blue, will also be available."

The Point Orange was designed by Metasphere from the outset to be a self-contained, low cost fit-and-forget unit for use in harsh and hazardous environments in remote locations. With the additional features Metasphere has included, the concept of continuous, real-time, pertinent data capture is now available to everyone in the industry. With access to this level of information, efficiency improves, with wastage significantly reduced, which ultimately lowers costs.