Units

Units describe physical measurements such as temperature, pressure, or energy. Set a property's semanticType to the quantity it measures so Sixb can validate the unit supplied with each telemetry reading.

Define a measurement

This sensor records temperature over time:

// ontology/sensor.ts
import { defineObjectType, prop } from "@sixb/core/ontology"

export const Sensor = defineObjectType({
  id: "Sensor",
  name: "Sensor",
  properties: [
    prop("id", "string", { required: true, primary: true }),
    prop("temperature", "double", {
      mode: "telemetry",
      semanticType: "Temperature",
    }),
  ],
})

Use a numeric schema such as "double", "integer", or "decimal". For measurements reused across types, you can also put semanticType on a value type: every property that references it with valueTypeRef() takes units from that quantity.

Supply a unit

When appending a reading to an existing sensor, include its unit ID:

import { Sensor } from "./ontology/sensor"

await sixb.objects(Sensor).byId("sensor-1").telemetry(Sensor.p.temperature).append({
  value: 21.5,
  unit: "degreeCelsius",
  at: new Date(),
})

A property with a semantic type requires a unit from that quantity. Temperature accepts degreeCelsius, degreeFahrenheit, or kelvin; a pressure unit is rejected. Properties without a semantic type do not accept units.

Sixb validates and preserves the supplied value and unit. It does not convert readings to a common unit. Normalize units in your ingestion code or a pipeline when you need consistent values for comparison or aggregation.

See Telemetry for reading history and importing values in batches.

Find available units

Use getUnitsFor() to list a quantity's unit IDs and display symbols. Use getUnitSymbol() when rendering a known unit:

import { getUnitsFor, getUnitSymbol } from "@sixb/core/ontology"

const temperatureUnits = getUnitsFor("Temperature")
const symbol = getUnitSymbol("degreeCelsius") // "°C"

Other quantities include Pressure, Power, Energy, and Length. Browse the complete catalog through the exported quantitativeTypes object; QuantitativeTypeId provides its IDs as a TypeScript union.