V2/Concepts/Intro to Measurement

Measurement

Senfi deals with time seriesdata that can originate from a device or a complex system. Each record in this time series consists of:

• a timestamp indicating when the data was sampled (in milliseconds)
• a fixed set of tags
• a fixed set of metrics

All these records are kept in a dataset called a measurement. A measurement has a name (for display) and code (for integration).

Measurement Code

A measurement code is a unique identifier of this measurement. You can use a combination of lowercase alphanumeric characters and underscore.

• The naming convention of a measurement code is as follows: <vendor>_<system>_<version>
• For example: nest_thermostat_v1. If you need to make changes to the measurement (eg. adding or removing metrics), you should create a new measurement with an incremented version, eg. nest_thermostat_v2.

A measurement code cannot be changed after creation

Timestamp

When sending a measurement to Senfi, timestamp is represented as tm_source, milliseconds since epoch.

Take note that timestamp refers to when the reading or measurement is taken, not when it is sent. There can be cases where readings are taken first, and sent in a batch later. In this case, the timestamp of the measurement will be older than the time of sending.