RUT956 Modbus TCP server register map


I’m trying to extract some data from a RUT956 via modbus TCP according to this register map:

It seems like from time to time only some of the registers are operational.
For example:

  • addr 1: System uptime → works
  • addr 3: Mobile signal strength → modbus timeout
  • addr 5: system temperature → modbus timeout
  • addr 7: system hostname → works

I’m running firmware: RUT9M_R_00.07.07.

Went to do something else in the meantime and someone else rebooted the machine (including the RUT) and when i came back, the communication was restored.

Tried a reboot later for another reason and the communication is broken again.

Seems that the register map is fine, as it sometimes works. But i can’t seem to grasp what goes wrong here. Especially as just some of the data registers break.

Does this sound familiar to anyone?

Thanks in advance

Just stopped the modbus tcp server, waited a couple of second, and then started it again. Then it seems to be working again.


I’ve attempted to recreate your experienced issue in different ways, but without success. Could there be other Modbus configurations, either serial or TCP, that might be interfering with those registers? Is this problem occurring with just one device, or are multiple devices affected? Also, was this problem present in previous firmware versions?

If the device is not currently in production, you could consider taking a backup (for device restoration to a previous state), then reset the device and check if the Modbus issues persist.

Kind regards,

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