Figure 6.1 – Functional diagram The device has four independent digital inputs for external control signals. To the inputs can be connected: • switching devices (buttons, switches, reed switches, relays, etc.); • sensors with output n-p-n -transistor with an open collector; • sensors with output p-n-p -transistor. The levels of the input signals are converted and processed in the matching unit and then sent to the digital signal processing unit that performs: • reassignment of inputs in accordance with the selected counting mode (see section 7.2 ); 30