is it possible to read Modbus register 0?
Hello M. Basiouny,
Could you clarify the use case for reading register 0?
Specifically, are you trying to read data from one of our Teltonika Networks devices, or from a third-party device such as a sensor or PLC?
If it is a Teltonika Networks device, all relevant information can be found on our Wiki. For example, documentation on RUT956 monitoring via Modbus is available at the following link: https://wiki.teltonika-networks.com/view/RUT956_Monitoring_via_Modbus
Please also note that register 0 cannot be read because the device (Teltonika RutOS) does not define any data at that address. While the Modbus protocol itself supports address 0, Teltonika’s register map starts at address 1, meaning any request to address 0 returns no valid data:
| Modbus Address | Mapped Parameter |
|---|---|
| Address 0 | No parameter mapped |
| Address 1 | First real parameter (System Uptime) |
Therefore, to read the first available parameter from a Teltonika Networks router, the register address must be set to 1.
Kind regards,
Zilvinas
from a third-party device such as a sensor or PLC?
Hello m.basiouny,
I apologize if my earlier response may have caused any confusion. Could you please confirm whether you are trying to read Register 0 from a Teltonika Networks device or a third-party device? This will help me assist you more accurately.