Telemetrie ist das, was Ihre Geräte über die Zeit messen und melden: Temperaturen, Füllstände, Zähler, Zustände.
The path of a reading
- A device sends a message (MQTT, HTTP, LoRaWAN, a gateway or a poller). The message is counted toward your monthly message allowance.
- The message enters your root flow, split into records (one per timestamp), with keys and values checked against the key rules.
- The Alarm rules block evaluates the device profile’s alarm rules.
- The Save telemetry block writes the record. Only this block stores telemetry: a branch without it stores nothing.
- The store keeps the message, updates the device’s latest value per key, and the minute job folds the numbers into 1-minute aggregates; hour and day rollups follow.
- Dashboards, the device’s Telemetry tab, flows and the API read from the latest values, the raw rows or the rollups, depending on the time window.
See How readings are stored and Hosts, the root flow and profile root flows.
Key facts
| Topic | Fact |
|---|---|
| Keys | Up to 64 characters from A-Z a-z 0-9 _ . -, case-sensitive. Prefixes _, fw_, current_fw_ and cfg. are reserved. |
| Values | Numbers, true/false, text up to 1,024 characters, JSON objects or arrays up to 4 KiB. Only numbers are charted and aggregated. |
| Timestamps | Milliseconds since the epoch, UTC. More than 10 minutes in the future is dropped (adjustable). |
| Duplicates | The same values at the same time for the same device are stored once. |
| Latest value | Moves only to a strictly newer timestamp. |
| Aggregates | 1-minute sum, count, min, max and last per numeric key, then hour and day rollups. |
| Retention | A class of 7, 30, 90, 365 or 1,095 days from your plan. Raw rows are kept at most 90 days. |
| Message allowance | Counted per month. Going over it never stops your devices. |
In this section
| Page | What it covers |
|---|---|
| How readings are stored | Message rows, the key dictionary, latest values, rollups |
| Telemetry keys | Key rules, reserved prefixes, raw, the key cap, profile key settings |
| Timestamps, late and duplicate readings | Device time and receive time, future and old readings, duplicates, outages |
| Numbers, text and true/false values | What charts read and how to store states |
| Aggregates and rollups | Buckets, the seven aggregate functions, increase for counters |
| How long data is kept | Retention classes and what each level of detail keeps |
| The device’s Telemetry tab | Latest values and the trend chart on the device page |
| Exporting data | CSV and Excel downloads, the API, the organisation export |
| The history API | GET /api/telemetry/series and latest, with examples |
| Derived values | Computing and storing new keys in a flow |
| Message quota and usage | What counts as a message, plan allowances, warnings |
Related sections
- Devices: connecting devices and the payload formats they send. See MQTT topics and payload reference.
- Dashboards: charts, tables and value cards. See Data sources and parameters.
- Flows: the root flow that stores the data, and flows that compute new values.