The built-in measuring instrument can be connected to up to four external temperature and humidity modules. The temperature measuring range for the sensors of the measuring instrument is 0.0 - 50.0 °C and the humidity measuring range is 0.0 - 99.9 % r. h.. The power is supplied by the built-in measuring instrument itself via a mains connection of 110 - 220 V AC. The integrated sensor supply can supply the connected sensors with 12 or 24 V DC in the built-in measuring instrument. As soon as the sensors are connected, they are detected automatically by the measuring instrument. The communication between the sensor modules and the measuring instrument takes place via an analogueue 4 - 20 mA signal. If several sensors are connected, the average measurement value of all sensors is displayed on the measuring instrument. This means that the built-in measuring instrument is used, for example, in event halls, restaurants or in public buildings to monitor the ambient conditions. ; The installati