NOTICE Pin 13 is an internal power supply, required for connecting of switching devices and sensors. If the power consumption of the input devices exceeds the load capacity of the internal power source (24 V), an external source with an output voltage of 12 to 34 V (recommended 24 V) is required. Scheme for connection of the switching devices to the inputs is shown in Figure 5.2 . Figure 5.2 – Connecting switching devices: 1) when the device is operating from an external power source; 2) when the device is operating from an internal power source The connection diagrams of passive sensors with an n-p-n -type transistor with an open collector output are shown in Figure 5.3 . 22