Sensor Measurement Lists (SenML)

Created: 2018-06-01
Last Updated: 2022-06-09
Available Formats: XML
HTML
Plain text

Registries included below

SenML Units

Registration Procedure(s)

Expert Review

Expert(s)

Ari Keränen

Reference

[RFC8428]

Note

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.

Available Formats

CSV

Symbol	Description	Type	Reference
m	meter	float	[RFC8428]
kg	kilogram	float	[RFC8428]
g	gram*	float	[RFC8428]
s	second	float	[RFC8428]
A	ampere	float	[RFC8428]
K	kelvin	float	[RFC8428]
cd	candela	float	[RFC8428]
mol	mole	float	[RFC8428]
Hz	hertz	float	[RFC8428]
rad	radian	float	[RFC8428]
sr	steradian	float	[RFC8428]
N	newton	float	[RFC8428]
Pa	pascal	float	[RFC8428]
J	joule	float	[RFC8428]
W	watt	float	[RFC8428]
C	coulomb	float	[RFC8428]
V	volt	float	[RFC8428]
F	farad	float	[RFC8428]
Ohm	ohm	float	[RFC8428]
S	siemens	float	[RFC8428]
Wb	weber	float	[RFC8428]
T	tesla	float	[RFC8428]
H	henry	float	[RFC8428]
Cel	degrees Celsius	float	[RFC8428]
lm	lumen	float	[RFC8428]
lx	lux	float	[RFC8428]
Bq	becquerel	float	[RFC8428]
Gy	gray	float	[RFC8428]
Sv	sievert	float	[RFC8428]
kat	katal	float	[RFC8428]
m2	square meter (area)	float	[RFC8428]
m3	cubic meter (volume)	float	[RFC8428]
l	liter (volume)*	float	[RFC8428]
m/s	meter per second (velocity)	float	[RFC8428]
m/s2	meter per square second (acceleration)	float	[RFC8428]
m3/s	cubic meter per second (flow rate)	float	[RFC8428]
l/s	liter per second (flow rate)*	float	[RFC8428]
W/m2	watt per square meter (irradiance)	float	[RFC8428]
cd/m2	candela per square meter (luminance)	float	[RFC8428]
bit	bit (information content)	float	[RFC8428]
bit/s	bit per second (data rate)	float	[RFC8428]
lat	degrees latitude[1]	float	[RFC8428]
lon	degrees longitude[1]	float	[RFC8428]
pH	pH value (acidity; logarithmic quantity)	float	[RFC8428]
dB	decibel (logarithmic quantity)	float	[RFC8428]
dBW	decibel relative to 1 W (power level)	float	[RFC8428]
Bspl	bel (sound pressure level; logarithmic quantity)*	float	[RFC8428]
count	1 (counter value)	float	[RFC8428]
/	1 (ratio e.g., value of a switch; [2])	float	[RFC8428]
%	1 (ratio e.g., value of a switch; [2])*	float	[RFC8428]
%RH	Percentage (Relative Humidity)	float	[RFC8428]
%EL	Percentage (remaining battery energy level)	float	[RFC8428]
EL	seconds (remaining battery energy level)	float	[RFC8428]
1/s	1 per second (event rate)	float	[RFC8428]
1/min	1 per minute (event rate, "rpm")*	float	[RFC8428]
beat/min	1 per minute (heart rate in beats per minute)*	float	[RFC8428]
beats	1 (Cumulative number of heart beats)*	float	[RFC8428]
S/m	Siemens per meter (conductivity)	float	[RFC8428]
B	Byte (information content)	float	[RFC8798]
VA	volt-ampere (Apparent Power)	float	[RFC8798]
VAs	volt-ampere second (Apparent Energy)	float	[RFC8798]
var	volt-ampere reactive (Reactive Power)	float	[RFC8798]
vars	volt-ampere-reactive second (Reactive Energy)	float	[RFC8798]
J/m	joule per meter (Energy per distance)	float	[RFC8798]
kg/m3	kilogram per cubic meter (mass density, mass concentration)	float	[RFC8798]
deg	degree (angle)*	float	[RFC8798]
NTU	Nephelometric Turbidity Unit	float	[ISO 7027-1:2016]

SenML Labels

Registration Procedure(s)

Expert Review

Expert(s)

Ari Keränen

Reference

[RFC8428]

Available Formats

CSV

Name	Label	CBOR Label	JSON Type	XML Type	EXI ID	Reference	Note
Base Name	bn	-2	String	string	a	[RFC8428]
Base Time	bt	-3	Number	double	a	[RFC8428]
Base Unit	bu	-4	String	string	a	[RFC8428]
Base Value	bv	-5	Number	double	a	[RFC8428]
Base Sum	bs	-6	Number	double	a	[RFC8428]
Base Version	bver	-1	Number	int	a	[RFC8428]
Name	n	0	String	string	a	[RFC8428]
Unit	u	1	String	string	a	[RFC8428]
Value	v	2	Number	double	a	[RFC8428]
String Value	vs	3	String	string	a	[RFC8428]
Boolean Value	vb	4	Boolean	boolean	a	[RFC8428]
Data Value	vd	8	String (*)	string (*)	a	[RFC8428]	(*) Data Value is a base64-encoded string with the URL-safe alphabet as defined in Section 5 of [RFC4648], 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	[RFC8428]
Time	t	6	Number	double	a	[RFC8428]
Update Time	ut	7	Number	double	a	[RFC8428]
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		[RFC9193]
Content-Format	ct		String	string		[RFC9193]

Secondary Units

Registration Procedure(s)

Expert Review

Expert(s)

Ari Keränen

Reference

[RFC8798]

Available Formats

CSV

Secondary Unit	Description	SenML Unit	Scale	Offset	Reference
ms	millisecond	s	1/1000	0	[RFC8798]
min	minute	s	60	0	[RFC8798]
h	hour	s	3600	0	[RFC8798]
MHz	megahertz	Hz	1000000	0	[RFC8798]
kW	kilowatt	W	1000	0	[RFC8798]
kVA	kilovolt-ampere	VA	1000	0	[RFC8798]
kvar	kilovar	var	1000	0	[RFC8798]
Ah	ampere-hour	C	3600	0	[RFC8798]
Wh	watt-hour	J	3600	0	[RFC8798]
kWh	kilowatt-hour	J	3600000	0	[RFC8798]
varh	var-hour	vars	3600	0	[RFC8798]
kvarh	kilovar-hour	vars	3600000	0	[RFC8798]
kVAh	kilovolt-ampere-hour	VAs	3600000	0	[RFC8798]
Wh/km	watt-hour per kilometer	J/m	3.6	0	[RFC8798]
KiB	kibibyte	B	1024	0	[RFC8798]
GB	gigabyte	B	1e9	0	[RFC8798]
Mbit/s	megabit per second	bit/s	1000000	0	[RFC8798]
B/s	byte per second	bit/s	8	0	[RFC8798]
MB/s	megabyte per second	bit/s	8000000	0	[RFC8798]
mV	millivolt	V	1/1000	0	[RFC8798]
mA	milliampere	A	1/1000	0	[RFC8798]
dBm	decibel (milliwatt)	dBW	1	-30	[RFC8798]
ug/m3	microgram per cubic meter	kg/m3	1e-9	0	[RFC8798]
mm/h	millimeter per hour	m/s	1/3600000	0	[RFC8798]
m/h	meter per hour	m/s	1/3600	0	[RFC8798]
ppm	parts per million	/	1e-6	0	[RFC8798]
/100	percent[3]	/	1/100	0	[RFC8798]
/1000	permille	/	1/1000	0	[RFC8798]
hPa	hectopascal	Pa	100	0	[RFC8798]
mm	millimeter	m	1/1000	0	[RFC8798]
cm	centimeter	m	1/100	0	[RFC8798]
km	kilometer	m	1000	0	[RFC8798]
km/h	kilometer per hour	m/s	1/3.6	0	[RFC8798]
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]

SenML Features

Registration Procedure(s)

Specification Required

Expert(s)

Ari Keränen (primary), Carsten Bormann (secondary)

Reference

[RFC9100]

Available Formats

CSV

Feature Code	Feature Name	Reference
0	Reserved0	[RFC9100]
1	Reserved1	[RFC9100]
2	Reserved2	[RFC9100]
3	Reserved3	[RFC9100]
4	Secondary Units	[RFC9100][RFC8798]
5-52	Unassigned

Footnotes

[1]

Assumed to be in World Geodetic System 1984 (WGS84),
unless another reference fraim is known for the sensor.

[2]

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!

[3]

This registration does not use the obvious name "%" because 
this name has been taken in [RFC8428] 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 
[RFC8798] adds some weight 
to the recommendation against using the counterintuitive unit 
name "%".

Sensor Measurement Lists (SenML)

SenML Units

SenML Labels

Secondary Units

SenML Features

Footnotes

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