Understanding water meter accuracy - and why dynamic range not necessarily says anything about it Water_meter_accuracy_GB_04-2017 Sometimes even straightforward things can puzzle your mind, if you scratch below the surface. Meter accuracy is one of these things. But since the water meter is what enables fair billing of the utility’s services and products, knowing what makes accuracy – and what does not – is key. Accuracy meets a lower dynamic range At Kamstrup, dynamic range is not a main focus during the development and production of water meters. They do not necessarily have the highest dynamic range in the market, but we are able to ensure very high accuracy by means of: The limits of the dynamic range In water metering, meters with a high dynamic range are sometimes mistaken for being more accurate than meters with a lower dynamic range. Albeit dynamic range relates to accuracy, there is no direct link between the two terms. In fact, dynamic range does not necessarily say anything about a meter’s actual measurement capability. Instead, it says a lot about the range of flow (usually ranging from a few drops to heavy usage) within which the authorities are testing a meter for type approval purposes. Accuracy in practice In practice, this means that a meter with a lower dynamic range can easily be more accurate than a high dynamic range one – you just do not have the authorities’ word for it. • A robust construction and strict component tolerance management, which render individual calibration and fine tuning superfluous • Databased calibration and adjustment, which ensure an error margin close to 0% in the entire dynamic range • Continuous tests of the meter batch in three flow rates, which enables proactive fine-tuning of calibration values and test of the entire dynamic range (i.e. temperature and flow) Make informed decisions – not just decisions Understanding meter accuracy does not have to be hard. Weight the facts and keep in mind that, if the authorities’ word (the dynamic range) matters the most to you, relate the error margin to consumer profilers (how your consumers consume water) to determine the actual impact. So to assess accuracy fairly, look beyond the dynamic range and take into account also lower start flow, accuracy within the maximum permissible error margin and measurement technique. These characteristics all affect accuracy. If, on the other hand, low flow is what matters the most, consider the actual measurement technique and meter longevity. Either way, if accuracy is important to you, know the impact of the error margin. Kamstrup A/S · Industrivej 28, Stilling · DK-8660 Skanderborg · T: +45 89 93 10 00 · info@kamstrup.com · kamstrup.com
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