The very idea for KNX originated in 1990 in Brussels, Belgium, where the 15 largest electrical equipment manufacturers founded the European Installation Bus Association, i.e. EIBA. The idea was to implement electrical installations with a bus topology in the future. This is followed by accelerated development and the first computer software for the use of the EIB itself, the so-called Engineering Tool Software i.e. ETS. After the successful first version of ETS, newer versions came in the future. The first trainings for use and implementation are established and the first device using the EIB system is created. After that, the EIB merged with two other associations and in 2006 they were renamed KNX. Today, KNX has almost 500 manufacturers worldwide and has a constant development in terms of both the number of users and the improvement of the equipment itself. Devices that were made 25 years ago and were immediately put into production are still used today, which speaks of high standards in the manufacture of KNX devices. Due to such a high standard, it is necessary to monitor the temperature during the manufacturing process of the device itself. The temperature through which the devices pass is very high and cannot be measured easily, e.g. with a thermometer. In addition to measuring high temperature, it is necessary to send data on the current temperature and the temperature condition must be documented later. Such a device that goes through the entire manufacturing process and sends the necessary data via radio frequency is the device described in this paper.