RUT956 – IEC 60870-5-104 Server: Spontaneous (Cot=3) and Cyclic (Cot=1) transmission options missing for user-defined Modbus data points

Networking Solutions Question
1

Hello Teltonika Support Team,

I am configuring a standard data bridge on a RUT956 router (RutOS) using the native WebUI services. My setup is as follows:

  1. The router acts as a Modbus TCP Master (Client) and successfully reads data registers from an external Modbus TCP Slave device.
  2. These registers are mapped into the native IEC 60870-5-104 Server as custom, user-defined Information Objects (IOA) to be read by an upstream SCADA Master.

The data mapping itself works fine, but I am facing a critical issue with data transmission states to the SCADA Master:

  1. When the values in the Modbus registers change, the IEC 104 Server does not transmit these updates spontaneously (Cot=3) to the SCADA Master.
  2. The SCADA Master only receives the updated values when it explicitly requests a General Interrogation (GA).
  3. In the WebUI configuration of the IEC 104 Server, I noticed that the option to select the transmission type (Spontaneous / Cyclic) is only available for pre-defined system parameters (like system time, temperature, etc.), but it is completely missing for custom, user-defined data points mapped from Modbus. There is currently no way to configure either spontaneous or cyclic data push for these points.

Without these options, our SCADA system cannot receive updates efficiently without constantly polling the router with GA commands. Having the ability to set either Spontaneous or even Cyclic transmission for custom Modbus points would fully resolve our issue.

Questions:

  1. Is there a hidden configuration or a specific workaround in RutOS to enable spontaneous or cyclic transmission for user-defined Modbus points in the IEC 104 Server?
  2. If this is a known limitation of the current firmware implementation, is there a plan to add the “Transmission Type” (Spontaneous / Cyclic) options for custom Modbus data points in an upcoming RutOS release?

Thank you for your support and advice.

Best regards,
Robert

3

Hello @roboj,

Thank you for reaching out to us.

We will forward your questions to our R&D department for further review.

We would also like to examine the device’s logs to help us investigate the issue further.

For this, we will need the device’s troubleshooting file, which may contain sensitive information such as passwords, public IP addresses, serial numbers, and other potentially confidential data.

To ensure this information is shared securely, we have sent you a form to complete. You should receive it at the email address associated with your Community Forum account.

When completing the form, please enter 21602 in the Ticket ID field so that we can associate the submitted information with this forum thread.

Thank you for your patience and cooperation. We look forward to receiving the requested information.

Best regards,
P.