RUT 956 - Modbus - DataToServer

i have a Problem with the Function DataToServer and Modbus DATA.


  • Modbus Serial Server is on
  • Modbus Serial Client is on, the Request Configuration ist working proberly (Request Configuration Testing)
  • DataToServer ist working with Base Data, MNF info, etc. BUT NOT with Modbus Data!

The Result from the MQTT Explorer/Brocker on an other Server is:
“Modbus”: “N/A”,
“Base”: “RUT95620XXXX”

The “N/A” in the MQTT Explorer is the entry from the general DataToServer Collection and NOT from the “1 Modbus” Data Input Entry.

Any Ideas?


Please, make sure that Modbus requests are enabled and the period is configured correctly:

Also, do not forget to turn on the Modbus Client itself:

Kind Regards,

Modbus requests and the Modbus SERIAL Client are enabled. The period is 10.

I’m wondering because in the MQTT Explorer there ist an “N/A” from the DataServer (First Line of the ScreenShot) an not an “Empty” from the second line (Modbus Data Input).

The question is whether the DataServer (line 1) gets data from the Modbus definition (line 2). I think, if there are no modbus data, there must be an “empty”.


Do you have a serial Mobus server connected to RUT956?

Could you please share screenshots of your configurations?

Kind Regards,

I put some screenshots and a description into a PDF file. This can be done via the following link. Unfortunately, I cannot attach multiple screenshots or files here.

I had already used the Modbus configuration with the old OS on a RUT 955. But because of IPV6 I had to switch to the new OS and a new router.

Descripton and Screenshots


It seems that the link is not working. Could you please share the screenshots here?

Kind Regards,

ok then there will be a lot of posts because …
An error occurred: Sorry, new users can only put one embedded media item in a post.

here are the complete configuration:

Configuration ModBUS Serial RUT 956
(Firmware RUT9M_R_00.07.05.4)


Modbus Serial Server:

Modbus Serial Client


Data to Server:


The Entry for the emty value ist “N/A” !

Rest of Server Configuration:


Could you please try enabling the Modbus Serial Device?

Let me know how it goes.

Kind Regards,

Sorry for the lon response time.
But I reached my maximum possible posts yesterday.

I can enable the SerialServer OR the Modbus Serial Device Configuration. Not both.


Now, I have disabled the Serial Server and enabled the Modbus Serial Device Configuration.
Thats how it works. I thought the serial server was also required.

Thanks a lot for Troubleshooting


Only one service can use a serial interface. If you had Modbus Serial Server configured, this means that the device will act as a server and other services will not be able to use this serial connection. Since you are reading modbus data from other devices, you need to configure Modbus Serial Client (the RUT will send requests to the server).

Kind Regards,

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