UnitSymbol

Class Description

The derived units defined for usage in the CIM. In some cases, the derived unit is equal to an SI unit. Whenever possible, the standard derived symbol is used instead of the formula for the derived unit. For example, the unit symbol Farad is defined as "F" instead of "CPerV". In cases where a standard symbol does not exist for a derived unit, the formula for the unit is used as the unit symbol. For example, density does not have a standard symbol and so it is represented as "kgPerm3". With the exception of the "kg", which is an SI unit, the unit symbols do not contain multipliers and therefore represent the base derived unit to which a multiplier can be applied as a whole. Every unit symbol is treated as an unparseable text as if it were a single-letter symbol. The meaning of each unit symbol is defined by the accompanying descriptive text and not by the text contents of the unit symbol. To allow the widest possible range of serializations without requiring special character handling, several substitutions are made which deviate from the format described in IEC 80000-1. The division symbol "/" is replaced by the letters "Per". Exponents are written in plain text after the unit as "m3" instead of being formatted as "m" with a superscript of 3 or introducing a symbol as in "m^3". The degree symbol "°" is replaced with the letters "deg". Any clarification of the meaning for a substitution is included in the description for the unit symbol. Non-SI units are included in list of unit symbols to allow sources of data to be correctly labelled with their non-SI units (for example, a GPS sensor that is reporting numbers that represent feet instead of meters). This allows software to use the unit symbol information correctly convert and scale the raw data of those sources into SI-based units. The integer values are used for harmonization with IEC 61850.

Attributes

Name	Type	Description
A		Current in amperes.
A2		Amperes squared (A²).
A2h		Ampere-squared hour, ampere-squared hour.
A2s		Ampere squared time in square amperes (A²s).
APerA		Current, ratio of amperages. Note: Users may need to supply a prefix such as ‘m’ to show rates such as ‘mA/A’.
APerm		A/m, magnetic field strength, amperes per metre.
Ah		Ampere-hours, ampere-hours.
As		Ampere seconds (A·s).
Bq		Radioactivity in becquerels (1/s).
Btu		Energy, British Thermal Units.
C		Electric charge in coulombs (A·s).
CPerkg		Exposure (x rays), coulombs per kilogram.
CPerm2		Surface charge density, coulombs per square metre.
CPerm3		Electric charge density, coulombs per cubic metre.
F		Electric capacitance in farads (C/V).
FPerm		Permittivity, farads per metre.
G		Magnetic flux density, gausses (1 G = 10-4 T).
Gy		Absorbed dose in grays (J/kg).
GyPers		Absorbed dose rate, grays per second.
H		Electric inductance in henrys (Wb/A).
HPerm		Permeability, henrys per metre.
Hz		Frequency in hertz (1/s).
HzPerHz		Frequency, rate of frequency change. Note: Users may need to supply a prefix such as ‘m’ to show rates such as ‘mHz/Hz’.
HzPers		Rate of change of frequency in hertz per second.
J		Energy in joules (N·m = C·V = W·s).
JPerK		Heat capacity in joules/kelvin.
JPerkg		Specific energy, Joules / kg.
JPerkgK		Specific heat capacity, specific entropy, joules per kilogram Kelvin.
JPerm2		Insulation energy density, joules per square metre or watt second per square metre.
JPerm3		Energy density, joules per cubic metre.
JPermol		Molar energy, joules per mole.
JPermolK		Molar entropy, molar heat capacity, joules per mole kelvin.
JPers		Energy rate in joules per second (J/s).
K		Temperature in kelvins.
KPers		Temperature change rate in kelvins per second.
M		Length, nautical miles (1 M = 1852 m).
Mx		Magnetic flux, maxwells (1 Mx = 10-8 Wb).
N		Force in newtons (kg·m/s²).
NPerm		Surface tension, newton per metre.
Nm		Moment of force, newton metres.
Oe		Magnetic field in oersteds, (1 Oe = (103/4p) A/m).
Pa		Pressure in pascals (N/m²). Note: the absolute or relative measurement of pressure is implied with this entry. See below for more explicit forms.
PaPers		Pressure change rate in pascals per second.
Pas		Dynamic viscosity, pascal seconds.
Q		Quantity power, Q.
Qh		Quantity energy, Qh.
S		Conductance in siemens.
SPerm		Conductance per length (F/m).
Sv		Dose equivalent in sieverts (J/kg).
T		Magnetic flux density in teslas (Wb/m2).
V		Electric potential in volts (W/A).
V2		Volt squared (W²/A²).
V2h		Volt-squared hour, volt-squared-hours.
VA		Apparent power in volt amperes. See also real power and reactive power.
VAh		Apparent energy in volt ampere hours.
VAr		Reactive power in volt amperes reactive. The “reactive” or “imaginary” component of electrical power (VIsin(phi)). (See also real power and apparent power). Note: Different meter designs use different methods to arrive at their results. Some meters may compute reactive power as an arithmetic value, while others compute the value vectorially. The data consumer should determine the method in use and the suitability of the measurement for the intended purpose.
VArh		Reactive energy in volt ampere reactive hours.
VPerHz		Magnetic flux in volt per hertz.
VPerV		Voltage, ratio of voltages. Note: Users may need to supply a prefix such as ‘m’ to show rates such as ‘mV/V’.
VPerVA		Power factor, PF, the ratio of the active power to the apparent power. Note: The sign convention used for power factor will differ between IEC meters and EEI (ANSI) meters. It is assumed that the data consumers understand the type of meter being used and agree on the sign convention in use at any given utility.
VPerVAr		Power factor, PF, the ratio of the active power to the apparent power. Note: The sign convention used for power factor will differ between IEC meters and EEI (ANSI) meters. It is assumed that the data consumers understand the type of meter being used and agree on the sign convention in use at any given utility.
VPerm		Electric field strength, volts per metre.
Vh		Volt-hour, Volt hours.
Vs		Volt seconds (Ws/A).
W		Real power in watts (J/s). Electrical power may have real and reactive components. The real portion of electrical power (I²R or VIcos(phi)), is expressed in Watts. See also apparent power and reactive power.
WPerA		Active power per current flow, watts per Ampere.
WPerW		Signal Strength, ratio of power. Note: Users may need to supply a prefix such as ‘m’ to show rates such as ‘mW/W’.
WPerm2		Heat flux density, irradiance, watts per square metre.
WPerm2sr		Radiance, watts per square metre steradian.
WPermK		Thermal conductivity in watt/metres kelvin.
WPers		Ramp rate in watts per second.
WPersr		Radiant intensity, watts per steradian.
Wb		Magnetic flux in webers (V·s).
Wh		Real energy in watt hours.
anglemin		Plane angle, minutes.
anglesec		Plane angle, seconds.
bar		Pressure in bars, (1 bar = 100 kPa).
cd		Luminous intensity in candelas.
charPers		Data rate (baud) in characters per second.
character		Number of characters.
cosPhi		Power factor, dimensionless. Note 1: This definition of power factor only holds for balanced systems. See the alternative definition under code 153. Note 2 : Beware of differing sign conventions in use between the IEC and EEI. It is assumed that the data consumer understands the type of meter in use and the sign convention in use by the utility.
count		Amount of substance, Counter value.
d		Time in days, day = 24 h = 86400 s.
dB		Sound pressure level in decibels. Note: multiplier “d” is included in this unit symbol for compatibility with IEC 61850-7-3.
dBm		Power level (logarithmic ratio of signal strength , Bel-mW), normalized to 1mW. Note: multiplier “d” is included in this unit symbol for compatibility with IEC 61850-7-3.
deg		Plane angle in degrees.
degC		Relative temperature in degrees Celsius. In the SI unit system the symbol is °C. Electric charge is measured in coulomb that has the unit symbol C. To distinguish degree Celsius from coulomb the symbol used in the UML is degC. The reason for not using °C is that the special character ° is difficult to manage in software.
ft3		Volume, cubic feet.
gPerg		Concentration, The ratio of the mass of a solute divided by the mass of the solution. Note: Users may need use a prefix such a ‘µ’ to express a quantity such as ‘µg/g’.
gal		Volume in gallons, US gallon (1 gal = 231 in3 = 128 fl ounce).
h		Time in hours, hour = 60 min = 3600 s.
ha		Area, hectares.
kat		Catalytic activity, katal = mol / s.
katPerm3		Catalytic activity concentration, katals per cubic metre.
kg		Mass in kilograms. Note: multiplier “k” is included in this unit symbol for compatibility with IEC 61850-7-3.
kgPerJ		Weight per energy in kilograms per joule (kg/J). Note: multiplier “k” is included in this unit symbol for compatibility with IEC 61850-7-3.
kgPerm3		Density in kilogram/cubic metres (kg/m³). Note: multiplier “k” is included in this unit symbol for compatibility with IEC 61850-7-3.
kgm		Moment of mass in kilogram metres (kg·m) (first moment of mass). Note: multiplier “k” is included in this unit symbol for compatibility with IEC 61850-7-3.
kgm2		Moment of mass in kilogram square metres (kg·m²) (Second moment of mass, commonly called the moment of inertia). Note: multiplier “k” is included in this unit symbol for compatibility with IEC 61850-7-3.
kn		Speed, knots (1 kn = 1852/3600) m/s.
l		Volume in litres, litre = dm3 = m3/1000.
lPerh		Volumetric flow rate, litres per hour.
lPerl		Concentration, The ratio of the volume of a solute divided by the volume of the solution. Note: Users may need use a prefix such a ‘µ’ to express a quantity such as ‘µL/L’.
lPers		Volumetric flow rate in litres per second.
lm		Luminous flux in lumens (cd·sr).
lx		Illuminance in lux (lm/m²).
m		Length in metres.
m2		Area in square metres (m²).
m2Pers		Viscosity in square metres / second (m²/s).
m3		Volume in cubic metres (m³).
m3Compensated		Volume, cubic metres, with the value compensated for weather effects.
m3Perh		Volumetric flow rate, cubic metres per hour.
m3Perkg		Specific volume, cubic metres per kilogram, v.
m3Pers		Volumetric flow rate in cubic metres per second (m³/s).
m3Uncompensated		Volume, cubic metres, with the value uncompensated for weather effects.
mPerm3		Fuel efficiency in metres per cubic metres (m/m³).
mPers		Velocity in metres per second (m/s).
mPers2		Acceleration in metres per second squared (m/s²).
min		Time in minutes, minute = 60 s.
mmHg		Pressure, millimetres of mercury (1 mmHg is approximately 133.3 Pa).
mol		Amount of substance in moles.
molPerkg		Concentration, Molality, the amount of solute in moles and the amount of solvent in kilograms.
molPerm3		Concentration, The amount of substance concentration, (c), the amount of solvent in moles divided by the volume of solution in m³.
molPermol		Concentration, Molar fraction, the ratio of the molar amount of a solute divided by the molar amount of the solution.
none		Dimension less quantity, e.g. count, per unit, etc.
ohm		Electric resistance in ohms (V/A).
ohmPerm		Electric resistance per length in ohms per metre ((V/A)/m).
ohmm		Resistivity, ohm metres, (rho).
onePerHz		Reciprocal of frequency (1/Hz).
onePerm		Wavenumber, reciprocal metres, (1/m).
ppm		Concentration in parts per million.
rad		Plane angle in radians (m/m).
radPers		Angular velocity in radians per second (rad/s).
radPers2		Angular acceleration, radians per second squared.
rev		Amount of rotation, revolutions.
rotPers		Rotations per second (1/s). See also Hz (1/s).
s		Time in seconds.
sPers		Time, Ratio of time. Note: Users may need to supply a prefix such as ‘µ’ to show rates such as ‘µs/s’.
sr		Solid angle in steradians (m2/m2).
therm		Energy, therms.
tonne		Mass in tons, “tonne” or “metric ton” (1000 kg = 1 Mg).

Relationships

Ancestors

No ancestor classes

Descendents

No descendent classes

Associations

None