2018-06-01 2026-02-02 In SDF , a URI unit name is distinguished from a registered unit name by the presence of a colon; any registered unit name that contains a colon can therefore not be directly used in SDF. Expert Review Ari Keränen Units marked with an asterisk are NOT RECOMMENDED to be produced by new implementations but are in active use and SHOULD be implemented by consumers that can use the corresponding SenML units that are closer to the unscaled SI units. m meter float kg kilogram float g gram* float s second float A ampere float K kelvin float cd candela float mol mole float Hz hertz float rad radian float sr steradian float N newton float Pa pascal float J joule float W watt float C coulomb float V volt float F farad float Ohm ohm float S siemens float Wb weber float T tesla float H henry float Cel degrees Celsius float lm lumen float lx lux float Bq becquerel float Gy gray float Sv sievert float kat katal float m2 square meter (area) float m3 cubic meter (volume) float l liter (volume)* float m/s meter per second (velocity) float m/s2 meter per square second (acceleration) float m3/s cubic meter per second (flow rate) float l/s liter per second (flow rate)* float W/m2 watt per square meter (irradiance) float cd/m2 candela per square meter (luminance) float bit bit (information content) float bit/s bit per second (data rate) float lat degrees latitude float lon degrees longitude float pH pH value (acidity; logarithmic quantity) float dB decibel (logarithmic quantity) float dBW decibel relative to 1 W (power level) float Bspl bel (sound pressure level; logarithmic quantity)* float count 1 (counter value) float / 1 (ratio e.g., value of a switch; ) float % 1 (ratio e.g., value of a switch; )* float %RH Percentage (Relative Humidity) float %EL Percentage (remaining battery energy level) float EL seconds (remaining battery energy level) float 1/s 1 per second (event rate) float 1/min 1 per minute (event rate, "rpm")* float beat/min 1 per minute (heart rate in beats per minute)* float beats 1 (Cumulative number of heart beats)* float S/m Siemens per meter (conductivity) float B Byte (information content) float VA volt-ampere (Apparent Power) float VAs volt-ampere second (Apparent Energy) float var volt-ampere reactive (Reactive Power) float vars volt-ampere-reactive second (Reactive Energy) float J/m joule per meter (Energy per distance) float kg/m3 kilogram per cubic meter (mass density, mass concentration) float deg degree (angle)* float NTU Nephelometric Turbidity Unit float ISO 7027-1:2016 Assumed to be in World Geodetic System 1984 (WGS84), unless another reference frame is known for the sensor. A value of 0.0 indicates the switch is off, 1.0 indicates on, and 0.5 indicates half on. The preferred name of this unit is "/". For historical reasons, the name "%" is also provided for the same unit, but note that while that name strongly suggests a percentage (0..100), it is NOT a percentage but the absolute ratio! This registration does not use the obvious name "%" because this name has been taken in already, where it is a NOT RECOMMENDED synonym for "/" (unity) for legacy reasons. Note that the presence of both "%" and "/100" with different meanings is likely to create confusion, so adds some weight to the recommendation against using the counterintuitive unit name "%". Expert Review Ari Keränen Base Name bn -2 String string a Base Time bt -3 Number double a Base Unit bu -4 String string a Base Value bv -5 Number double a Base Sum bs -6 Number double a Base Version bver -1 Number int a Name n 0 String string a Unit u 1 String string a Value v 2 Number double a String Value vs 3 String string a Boolean Value vb 4 Boolean boolean a Data Value vd 8 String (*) string (*) a (*) Data Value is a base64-encoded string with the URL-safe alphabet as defined in Section 5 of , with padding omitted. (In CBOR, the octets in the Data Value are encoded using a definite-length byte string, major type 2.) Sum s 5 Number double a Time t 6 Number double a Update Time ut 7 Number double a LwM2M Object Link vlo String string OMA-TS-LightweightM2M_Core-V1_1_1-20190617-A Section 7.4.5 of the OMA LwM2M 1.1 Core Technical Specification Base Content-Format bct String string Content-Format ct String string Expert Review Ari Keränen ms millisecond s 1/1000 0 min minute s 60 0 h hour s 3600 0 MHz megahertz Hz 1000000 0 kW kilowatt W 1000 0 kVA kilovolt-ampere VA 1000 0 kvar kilovar var 1000 0 Ah ampere-hour C 3600 0 Wh watt-hour J 3600 0 kWh kilowatt-hour J 3600000 0 varh var-hour vars 3600 0 kvarh kilovar-hour vars 3600000 0 kVAh kilovolt-ampere-hour VAs 3600000 0 Wh/km watt-hour per kilometer J/m 3.6 0 KiB kibibyte B 1024 0 GB gigabyte B 1e9 0 Mbit/s megabit per second bit/s 1000000 0 B/s byte per second bit/s 8 0 MB/s megabyte per second bit/s 8000000 0 mV millivolt V 1/1000 0 mA milliampere A 1/1000 0 dBm decibel (milliwatt) dBW 1 -30 ug/m3 microgram per cubic meter kg/m3 1e-9 0 mm/h millimeter per hour m/s 1/3600000 0 m/h meter per hour m/s 1/3600 0 ppm parts per million / 1e-6 0 /100 percent / 1/100 0 /1000 permille / 1/1000 0 hPa hectopascal Pa 100 0 mm millimeter m 1/1000 0 cm centimeter m 1/100 0 km kilometer m 1000 0 km/h kilometer per hour m/s 1/3.6 0 ppb parts per billion / 1e-9 0 CoRE-1 ppt parts per trillion / 1e-12 0 CoRE-1 VAh volt-ampere-hour VAs 3600 0 CoRE-1 mg/l milligram per liter kg/m3 1/1000 0 CoRE-1 ug/l microgram per liter kg/m3 1e-6 0 CoRE-1 g/l gram per liter kg/m3 1 0 CoRE-1 Specification Required Ari Keränen (primary), Carsten Bormann (secondary) 0 Reserved0 1 Reserved1 2 Reserved2 3 Reserved3 4 Secondary Units 5-52 Unassigned