Modbus TCP

With Modbus TCP, the measured values of a device can be queried directly via the network connection. No detour via the cloud is necessary.

Requirements

To activate Modbus TCP you need a smart-me Professional subscription

Supported devices

The following smart-me devices support Modbus TCP:

3-phase meter telstar all versions

3-phase meter from firmware version 3.0

L+G module all versions

Kamstrup module from firmware version 8.0


Note: Modbus TCP for local communication without stable Internet access (interruptions) is only possible with the Telstar 80A and Telstar CT series meters. The other devices and modules cannot offer stable Modbus communication without a constant Internet connection.

Activate Modbus TCP

  1. Log in on the smart-me website or in the smart-me app.

  2. Select the desired device

  3. Click on "edit"

  4. Switch on "Modbus TCP" under the "Advanced Settings"

Find the address of the device

To read a device with Modbus TCP, you need to know the address of this device. The smart-me devices obtain the IP address from the local DHCP server. There are two ways to find the address:

  1. Enable DNS: The easiest way to connect to a smart-me device in the local network is to enable the automatic DNS update. More information: Dynamic DNS

  2. Configure DHCP / Router Server: Another way to find out the IP address of a smart-me meter is to look it up on your router or DHCP server. Search for an entry with a MAC address which begins with "D0 :".

Modbus TCP Protokoll

TCP Port: 502

Functions

The smart-me Meter supports the following Modbus functions:

  • Read Holding Register (Code 03)

Register Addressing

For historical reasons the address in Modbus is 1 lower than the internal register address. So the start address has to be (Registeraddress - 1)

Register Addressing