RUT200 Modbus TCP/IP Server

Networking Solutions
1

Good morning, I bought a RUT200 to test the VPN connection. Everything works fine and without problems.
I also configured the RUT200 as a Modbus TCP Client and everything works correctly.
When I configured the RUT200 as a Modbus TCP/IP Master, I found that reading the “Send SMS 397” and “ADD SMS 398” registers worked correctly, but when I tried to write the “ADD SMS” registers, the RUT200 responded with the H02 “illegal address” error. Basically, I can read but not write, and I can’t figure out why. I’ve tried everything, but to no avail.
However, there are no problems with the user-configurable addresses starting at address 1025. I read and write them without problems.
Do I need to configure something to be able to write the Modbus registers in the RUT200?
I need to update the ADD SMS addresses to configure SMS sending from an HMI connected to the RUT200 via the Modbus TCP/IP protocol.

RUT200 Firmware RUT2M_R_00.07.19
If anyone can help me, thank you.

3

Hello,

To answer your question:

Do I need to configure something to be able to write the Modbus registers in the RUT200?

Shortly, yes, you need to have the Modbus TCP Server (previously referred to as slave) enabled on the RUT200 in order to write to its registers. Without the Modbus TCP Server active, the device will not accept write commands.

Additionally, there is a wiki documentation guide below describing the Modbus TCP Server SMS sending setup, which I believe matches the configuration you are trying to achieve:

You may also find it helpful to review the related community thread discussing a similar SMS sending over Modbus TCP scenario here:

Best regards,