How Transmitters Work

Content to be migrated and merged from Confluence (56786995, 103162267, 260767749). Suggested section order:

1. What a Transmitter is — one-vs-many resource trade-offs, MQTT client limits, 1:1 and 1:many edge node relationships
2. Sparkplug topic namespace — GROUP_ID / EDGE_NODE_ID / DEVICE_ID
3. Mapping to the tag tree — Sparkplug Descriptors and how tag path becomes topic path
4. Configuration examples — worked examples from "Transmitters and Tag Trees"
5. Multi-Tag Paths — bracket syntax, rules, and worked examples