# Heartbeats Along with uplink messages (events) triggered irregularly (such as sensor-triggered events), you can also receive periodical events that are triggered by time only. We call some of these events **Heartbeats.** ## **Introduction** Heartbeats are **mode-independent events triggered by time**. There are **3 heartbeats** defined in API 6, Heartbeat 1, Heartbeat 2, and Heartbeat 3. **Heartbeats 1 and 2** are identical yet individual and you can fine-tune their behavior and appended data with a lot of settings. **Heartbeat 3** is used for regular messages with MAC addresses and to control the Stupid modes and its settings are limited compared to HB 1 and 2. ### --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://ask.simplehw.eu/kb/simple-api-6-generation/modes/api-6-mode-independent-information-and-events_15237121/heartbeats.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.