Setting up a Teltonika RUT956 to push Modbus meters via webhook

Teltonika RUT956 (and similar Teltonika RUT-series routers with RS485) can poll Modbus meters and push readings to the platform without any custom scripting — using the built-in RutOS "Modbus Client" plus "Data to Server" features.

Hardware preparation

1. Wire your Modbus meters' RS485 to the RUT956 RS485 port (A↔A, B↔B, terminate the last device with 120Ω if the bus is long).
2. Each meter must have a unique Modbus slave ID on the bus. Configure this on the meter's display or DIP switches per the vendor manual.
3. Insert an IoT-grade SIM card with mobile data and check signal strength at the install location. Add an external LTE antenna if the location is shielded (basement, underground parking).

RutOS configuration (web UI)

1. Services → Modbus → Modbus Client. Add one slave per meter: name, IP (for Modbus TCP) or serial settings (for RTU), slave ID, and the register list. For cumulative kWh on Carlo Gavazzi EM24/EM340, poll register 52 (4 bytes, int32, scale ×0.1).

2. Services → Data to Server. Add a data sender:

   • Type: HTTP(S)
   • URL: the webhook URL from your Inbilit data source
   • Period: 3600 seconds for hourly push (or 300 for every 5 minutes)
   • Format: JSON, custom template producing the required {"readings":[...]} shape with point_id (= meter serial) and values.kwh
   • Custom headers: X-Webhook-Timestamp (current Unix seconds) and X-Webhook-Signature (computed via custom script — RutOS supports running a shell snippet to compute HMAC)

3. Test once manually. RutOS provides a "Test" button on the Data to Server entry. Confirm the platform returns 200 before leaving the install.

On the Inbilit side

1. Create a webhook data source first to obtain the URL and secret.
2. After the gateway delivers its first push, go to Analytics → Meters → "From Data Imports" and expand your source.
3. Click "New" on each discovered point_id to create its meter, assigning each to a building (and a tenant if you're billing per-meter).

If your installer is unfamiliar with HMAC signing in RutOS, the "Webhook setup checklist" and "Webhook returns 401" articles cover the specific format requirements.