KNX binary inputs are used to connect conventional alarm messages, fault messages, operating messages or status messages to the KNX bus. An EIB, KNX binary input detects a status change at its input. Depending on the ETS parameterization, a telegram is sent to the KNX bus. This information can then be integrated into other desired function logics (e.g. window open = heating standby / frost protection or alarm when the alarm system is active) or just for visualization on a display or touch panel. The binary inputs are often provided in the types 20V, 24V, 230V and are potential-free. Potential-free means that no external voltage (potentials) must be connected to the inputs of these binary inputs, since the contact voltage (usually 10-20V) is already provided by the binary input itself. The potential-free type is generally used for push buttons, switches, door contacts (magnetic or reed contacts), window contacts (magnetic contacts) or auxiliary contacts. Magnetic contacts must often only be applied with max. 20V DC. The 230 V type is often used to connect existing 230V AC signals to the bus in order to evaluate them. For example, for conventional 230V outdoor motion detectors, push buttons, switches or other messages from other systems. Pay attention to the technically required max. cable lengths between signal capture and binary input contact which you find in the manufacturer's instructions for the different types, in particular 20V, 24V and potential-free. Often these amount to max. 100m and should be installed in a protected way without inductive or capacitive interference, especially if critical conditions are to be monitored, such as meter readings for billing purposes (LIYCY lines, cable). eibabo also offers KNX binary inputs to record meter values. Almost all conventional water meters, electricity meters, gas meters, heat meters, etc. can be ordered (including S0 interface (pronounced S-Zero interface), which is used to transmit consumption readings for further processing in building automation. By means of a contact the interface sends a pulse, which corresponds to a certain value of the measured medium. The pulse value always depends on the manufacturer of the meter. If, for example a water meter with S0 interface is purchased, the pulse value is given on the meter or in the product description, for example, 10 liters = 1 pulse. That means, the contact closes and opens again (rising / falling edge, 30 ms = t_EIN = 120 ms 30 ms = T_AUS) as soon as 10 liters of water have been consumed, or simply, there is a signal as if you were operating a push button. These contacts can be evaluated by means of a KNX binary input application for measured value capture provided by the manufacturer. For this, potential-free 20V or 24V binary inputs are usually used as the contact voltage must not exceed max. 15V (S0 interface class B, short transmission paths) or max.27V (S0 interface class A, long transmission paths). In this eibabo catalog you can find everything in the field of EIB, KNX binary input, binary input device, binary input module, push-button interface, universal interface, input module, push button coupler, evaluation unit, made by ABB, Berker, Busch-Jaeger, Doepke, Eaton, Elsner, Elso, Eltako, Gira Hager, Issendorf, Jumo, Jung, Lingg & Janke, MDT, Merten, Peha, Siemens, Theben and Warema.