Figure 5.5 – Connection of p-n-p-sensors: a) active; b) passive Device has a dual switch for selecting, which of the types of sensors will work. It is located on the lateral side of the housing Щ1 and Щ2. For device in the H housing, the switch is located inside the housing (to access the switch, it is necessary to remove the device cover by unscrewing the four screws that fasten the cover to the base). Appearance of the switch is shown in Figure 5.6 . 25