How to connect a TME Ethernet Thermometer to a PCD over Modbus?

FAQ #101411

 

Problem
Since the documentation for this thermometer is very limited regarding Modbus it is only possible to connect it via reverse-engineering. This is why we did a test.

Solution
The thermometer has a Web-Interface. With the base IP address it is possible to connect to the thermometer and set an IP address that corresponds to the network.
Afterwards the thermometer can be connected to the network. The temperature is available over Modbus TCP on "Input Register" 0. It is a 16 bit signed value. If more than one thermometer is in the network, each thermometer needs a different IP address, since they all have UID 1. A small demo project for the SBC-Modbus and Engiby-Modbus solution is attached to this FAQ.
In the attached PG5 program example the thermometers have the addresses 172.16.1.66 and 172.16.1.64.

Status Register
The following "Input Register" 1 contains the status of the thermometer. It is 0 if the thermometer is working correctly and it changes to 1 in case of error. If necessary you can read 2 "Input Registers" 0 and 1. The first will contain the temperature and the second the status.