“Precision is not always about counting every drop, but about knowing which drops truly matter. In measurement, as in life, clarity often comes from what we choose to leave out.” – MJ Martin
In water, gas, and electric meters, dial truncation refers to how the meter’s internal mechanical or digital register is interpreted when being read or transmitted electronically, specifically, how many digits of the full reading are displayed or communicated to the utility system.
Here is a clear explanation of what that means and why it matters:
1. Definition
A metering device records total consumption (for example, in cubic metres of water, cubic feet of gas, or kilowatt-hours of electricity). The mechanical or digital register typically contains a full set of digits that represent the total usage, often more than the utility needs for billing.
Truncation is when some of the least significant digits (the smallest decimal increments) are not shown or transmitted. These digits represent partial units that are smaller than the billing resolution.
For example:
If a water meter register shows 1234.567 m³, and the utility only bills to the nearest cubic metre, the transmitted or displayed reading might be truncated to 1234 m³.
2. Mechanical (Dial) Meters
In older mechanical meters (especially water and gas meters), the dials on the face represent different place values, each showing tenths, ones, tens, hundreds, etc.
Utilities often ignore the smallest dial(s) to match the billing resolution. The truncated dials still turn and measure consumption accurately, but only the higher-value digits are recorded for billing.
Example:
A 6-dial water meter might measure down to 0.001 m³, but the billing system only records to 1 m³, meaning the last three dials are truncated.
3. Digital and AMI Meters
In modern digital meters or smart meters, truncation happens in software rather than visually.
For instance:
An Itron or Badger water endpoint might record an 8-digit reading but only transmit the most significant 6 digits to the headend system. The configuration (for example, 8&3, 8&2, or 8&1) defines how many total digits and how many decimal places are included in the transmitted value.
So, 8&3 means 8 total digits with 3 decimals (more precision), while 8&1 means 8 digits with only 1 decimal (less precision). The “truncated” portion is simply not sent over the network to reduce data volume and align with billing requirements.
4. Purpose of Truncation
To standardize readings to billing resolution. To reduce data storage and transmission size in AMI systems. To ensure consistency across meter types and customer classes.
5. Effect on Billing
Truncation slightly under-reports instantaneous usage (because partial units are dropped, not rounded), but over time this balances out because each subsequent reading captures the total cumulative consumption. The integrity of long-term billing is not affected.
6. Truncation by Meter Size
Most popular meters today offer up 8 numeric values. So the location of the decimal place varies by the size of the meter.
RESIDENTIAL METERS – These meters are typically found in houses. They vary in sizes from 1/2”, 5/8”, or 3/4”. The 8 numbers for consumption values are commonly set as 5 and 3. That is to say, 5 numbers to the left of the decimal place and 3 numbers to the right of the decimal place. In Canada, we normally use cubic metres for water consumption. So, the first digit to the left of the decimal place is one cubic metres or 1,000 litres. Whereas the first digit to the right of the decimal place is 100 litres, the second digit to the right of the decimal place is 10 litres, and the third digit is 1 litre.
Ultrasonic meters are extremely accurate and can read to the lowest volumes as small as a teaspoon of water. Older Positive Displacement (PD) meters do not read to such low volumes. But the three decimal point granularity of the residential register is warranted to capture all revenue at lowest of flows.
SMALL COMMERCIAL METERS – These meters are found in multiplexes and small businesses. They are often 1.0”, 1.5”, 2.0”, and 3.0”. The 8 numbers for consumption values are commonly set as 6 and 2. That is to say, 6 numbers to the left of the decimal place and 2 numbers to the right of the decimal place. Again, assuming that the water meter reads in cubic metres.
LARGE COMMERCIAL METERS – These meters are found in municipal buildings, schools, apartments, and larger businesses. They are often 4.0”, 6.0”, and 8.0”.The 8 numbers for consumption values are commonly set as 7 and 1. That is to say, 7 numbers to the left of the decimal place and 1 number to the right of the decimal place.
VERY LARGE COMMERCIAL METERS – These meters are found in utility DMA, factories, major office buildings, and very large businesses. They are often 10.0” and larger. The 8 numbers for consumption values are commonly set as 8 and 0. That is to say, 8 numbers to the left of the decimal place and 0 number to the right of the decimal place.
TRUNCATION – Therefore, if no values that are less then 1 cubic litre are desired, then all values to the right of the decimal place are removed or truncated away. A meter reading 12345.678 would be truncated to 12345 and the .678 would be removed. This is commonly done with larger meters greater than 4.0” in size.
7. The Difference Between Truncation and Translation
Yes, there is a clear and important difference between truncation and translation in metering systems. They are related concepts but serve very different purposes in how meter data is handled and interpreted.
Truncation
Truncation refers to the removal of digits or decimal places from the raw meter reading to match the billing or reporting precision. It is a mathematical and formatting operation, not a change in meaning. The underlying register reading on the meter remains accurate and complete, but only part of it is transmitted or displayed.
For example:
A water meter records 12345.678 m³, but the headend or billing system only needs whole cubic metres, so the transmitted value becomes 12345 m³. The data has not been interpreted differently—just shortened. This is truncation.
Translation
Translation, by contrast, refers to the conversion or interpretation of raw meter data from one format, unit, or structure into another. It is a logical conversion rather than a simple numeric shortening.
For example:
Translating a pulse count from a water meter into cubic metres or litres based on the pulse constant. Translating a register index (e.g., hexadecimal or binary data from an AMI endpoint) into a human-readable volume. Translating radio-transmitted data from an Itron ERT or Badger ORION endpoint into a standard register value in the utility’s headend system.
In short, translation changes the representation, while truncation limits the precision.
Analogy
Think of truncation as cropping a photo to focus on the main subject, while translation is changing the language of the caption beneath it. One reduces detail; the other changes interpretation.
In Practical Use
In modern AMI systems (e.g., Itron Temetra, Badger BEACON, Kamstrup READy), translation happens first, converting the encoded or raw meter data into engineering units like cubic metres or kilowatt-hours. Truncation then follows, adjusting how many digits or decimal places are displayed or billed. Together, they ensure the meter’s technical accuracy aligns with operational and billing requirements.
8. Summary
In metering systems, translation and truncation work together to convert raw consumption data into usable billing information.
Translation is the process of converting raw meter signals or encoded data, such as pulse counts, radio packets, or binary registers, into meaningful engineering units like cubic metres or kilowatt-hours. It ensures that the data accurately reflects physical consumption by applying scaling factors, pulse constants, or register conversions defined by the meter’s configuration.
Once translated, truncation occurs, removing unnecessary digits or decimal places to match the billing precision required by the utility. For example, a water meter reading of 1234.567 m³ may be translated from pulse data and then truncated to 1234 m³ for billing.
Translation provides meaning, while truncation provides clarity. Together, they ensure that metered data remains both technically accurate and operationally practical, forming a seamless bridge between field measurement and financial accountability.
About the Author:
Michael Martin is the Vice President of Technology with Metercor Inc., a Smart Meter, IoT, and Smart City systems integrator based in Canada. He has more than 40 years of experience in systems design for applications that use broadband networks, optical fibre, wireless, and digital communications technologies. He is a business and technology consultant. He was a senior executive consultant for 15 years with IBM, where he worked in the GBS Global Center of Competency for Energy and Utilities and the GTS Global Center of Excellence for Energy and Utilities. He is a founding partner and President of MICAN Communications and before that was President of Comlink Systems Limited and Ensat Broadcast Services, Inc., both divisions of Cygnal Technologies Corporation (CYN: TSX).
Martin served on the Board of Directors for TeraGo Inc (TGO: TSX) and on the Board of Directors for Avante Logixx Inc. (XX: TSX.V). He has served as a Member, SCC ISO-IEC JTC 1/SC-41 – Internet of Things and related technologies, ISO – International Organization for Standardization, and as a member of the NIST SP 500-325 Fog Computing Conceptual Model, National Institute of Standards and Technology. He served on the Board of Governors of the University of Ontario Institute of Technology (UOIT) [now Ontario Tech University] and on the Board of Advisers of five different Colleges in Ontario – Centennial College, Humber College, George Brown College, Durham College, Ryerson Polytechnic University [now Toronto Metropolitan University]. For 16 years he served on the Board of the Society of Motion Picture and Television Engineers (SMPTE), Toronto Section.
He holds three master’s degrees, in business (MBA), communication (MA), and education (MEd). As well, he has three undergraduate diplomas and seven certifications in business, computer programming, internetworking, project management, media, photography, and communication technology. He has completed over 60 next generation MOOC (Massive Open Online Courses) continuous education in a wide variety of topics, including: Economics, Python Programming, Internet of Things, Cloud, Artificial Intelligence and Cognitive systems, Blockchain, Agile, Big Data, Design Thinking, Security, Indigenous Canada awareness, and more.