DALI · Interface guide
SDI-12
Set up the queries the station sends to SDI-12 sensors, and find, identify or re-address a sensor on the bus.
SDI-12 is a low-power bus used by many environmental sensors. Each sensor on the bus has a one-character address. On this page you tell the station which sensors to ask for measurements, and you can check or change a sensor's address.
Who can open it: Admin and Factory.
The page has two cards: SDI-12 Master Configuration and Sensor Operations.
SDI-12 Master Configuration
Top of the card
| Control | Allowed values | What it does |
|---|---|---|
| Enable | On or off | Turns SDI-12 polling on or off. Saves as soon as you flip it. |
| Poll Delay (s) | 0.01 to 10 | Pause between polling cycles. It is saved together with the next Enable change or query save. |
Query list
One row per query: number, Sensor ID, Request Type, Request Number (or Default) and Reset Flag, with Edit and Del. + Add Query opens an empty form. A station takes up to 10 SDI-12 queries.
Query form
| Field | Allowed values | What it does |
|---|---|---|
| Sensor ID | One character: 0 to 9, A to Z, a to z | The address of the sensor to ask. |
| Request Type | Measurement (M), Concurrent (C), Measurement + CRC (MC), Concurrent + CRC (CC) | Which SDI-12 measurement command to send. The CRC variants ask the sensor to add a checksum to its answer. |
| Request Number | Default, or 0 to 9 | Selects an additional measurement the sensor offers (for example M1, M2). Default sends the plain command. Choosing 0 is the same as Default. |
| Reset Flag | No or Yes | Meant to reset the sensor when SDI-12 polling starts. It is saved with the query, but it is not confirmed to change anything on current firmware. Leave it at No unless Aeron support asks. |
Save stores the query. Cancel closes the form.
The values a query brings back are mapped to parameters on the Parameters page, where you pick the sensor, request and which value of the answer to use (1 to 10).
Sensor Operations
Tools for the sensor on the bus. The station sends the command and the page waits for the answer, checking every 2 seconds for up to 60 seconds.
| Operation | Fields | What it does |
|---|---|---|
| Check Sensor ID | None | Asks which address the connected sensor has. The Result shows it, for example "Sensor Address: 0". |
| Identify Sensor | None | Finds the address, then asks the sensor to identify itself. The Result shows the address and the sensor's identification (maker, model, version). |
| Change Sensor ID | Current Address, New Address (one character each) | Gives the sensor a new address. The Result shows the new address. |
Press Execute to run the operation. Status shows Waiting, the step in progress, then Done or Failed.
One sensor at a time
Check and Identify expect a single sensor on the bus. Connect the sensor on its own when you set or change its address. Always fill in both address boxes before changing an address: a blank New Address sets the sensor to 0.
Messages you may see
| Message | What it means | What to do |
|---|---|---|
| Maximum 10 queries allowed | The SDI-12 list is full. | Delete a query first. |
| Cannot delete. At least one query must remain. | The list keeps at least one query. | Edit the query instead, or switch SDI-12 off with Enable. |
| Sensor ID must be a single character (0-9, A-Z, a-z) | The address is empty or not a single letter or digit. | Enter one character. |
| No sensor detected | Identify got no answer to the address check. | Check wiring and power, and that only one sensor is connected. |
| Timeout (60s) | The sensor did not answer in 60 seconds, or the request was not accepted. | Check wiring and the addresses you entered, then try again. |
| Failed | The station reported that the operation failed. | Check the sensor and try again. |