Historian cap: 20 MB
4 values per CHDP
Broker fan-out enabled
Live bandwidth use
20 MB historian limit
Total bandwidth graph
Adjust the CHDP count, speed, consumers, and building bandwidth to find the breakpoint.
| Choice | Why it breaks | When it wins |
|---|
| MQTT | -- | Many subscribers need the same live state. Device publishes once, broker fans out. |
| OPC UA | -- | Excellent semantic model, SCADA/historian integration, security, structured nodes. |
| Modbus/BACnet polling | -- | Simple field reads, existing BMS/devices, direct request/response troubleshooting. |