Data Collection and Forwarding
Install or confirm the required drivers first, then add a southbound driver, configure tags, and monitor values. This section covers the complete workflow from device collection, tag configuration, and monitoring to northbound forwarding. Per-protocol parameters and examples are in Southbound Drivers.
Read this section in sidebar order:
- Create a Southbound Driver: create the node, groups, and tags
- Data Monitoring: confirm tags are collecting
- Modbus TCP Server Simulator: test collection without hardware
- Data Forwarding: create a northbound application and subscribe to southbound data
Key concepts
Drivers and Applications
Southbound drivers collect device data; northbound applications send data to a cloud platform or processing engine. You need at least one of each for protocol conversion. For custom development, see the SDK Tutorial.
Node
A node is an instance of a driver or application. One EMQX Neuron process can run many nodes; the core framework routes messages between them.
Group and Tag
A tag describes a device address, read/write attributes, and metadata such as precision. Tags belong to groups; each group has its own polling interval. Northbound nodes subscribe to southbound groups.
Configuration process
Create a southbound driver: pick the driver for the device protocol, create a node, and set connection parameters.
Configure groups and tags. You can also import tags in batch from Excel.
TIP
Repeat steps 1 and 2 until all required drivers, groups, and tags are created.
To send data to MQTT, the cloud, or a processing engine, go to Data Forwarding: create a northbound application and subscribe to southbound groups.
The overall process is shown below:
Configuration specification
| Object | Limit |
|---|---|
| Node name length | 128 characters |
| Tag name length | 128 characters |
| Tag address length | 128 characters |
| Tag description length | 256 characters |
| Group name length | 128 characters |
| Maximum groups per southbound driver | 512 |
| Maximum subscribed groups per northbound application | unlimited |
| Driver or application module name length | 32 characters |
| Driver or application file name length | 64 characters |
| Driver or application description length | 512 characters |
| Southbound driver collection interval | minimum 100 milliseconds |