There are mounted two sensors at the same position inside the preheat zone. The lower ones are used for counting the clips in the preheat zone and the upper ones are used to compare set and act position. The other ones, mounted before smart drive 1 and smart drive 2, are used to compare set and act position before the clips are entering the smart drive. The values of the sensors in the preheat zone create a reaction of the linear motors during the initialisation process, later on they only observe the correct initialisation (in case of fault they restart the initialisation process) while the line is running. The sensors on the smart drives always create a reaction, but until now they are not used because due to the more rigid BMS04 system they are not needed. All functions are described more in detail
in "20. Running line".