# Binary (ok / alarm) loggers Switch logic (NO/NC logic) This group of sensors contain all devices, which react to the change of the state of the monitored value including: water leakage sensors and open / close sensors. On top of the standard features, users can define the logic of the binary sensors - decide, if the switches shall behave as normally open (NO) or normally close (NC). * Normally open (NO) - a normally open contact is the one that remains open until a certain condition is satisfied. This is how the water leakage loggers behave - if there is now water, the switch is opened and the logger is in the “ok” state. Once the water leak is detected, the switch closes, and the logger changes its state to “alarm”. * Normally closed (NC) - a normally closed contact is the one that remains closed until a certain condition is satisfied. This is how the open / closed loggers behave - if the door is closed, the switch is closed and the logger is in the “ok” state. Once the door opens, the switch opens, and the logger changes its state to “alarm”. In order to change the switch logic, connect to the device, and from the settings menu select “Advanced” -> ”Calibration” -> “Calibration parameters” -> “Select a channel” -> “Reversed logic”. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.efento.io/nb-iot-loggers/sensor-specific-settings/binary-ok-alarm-loggers.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.