If you're holding a sensor and don't know where it belongs, there are a few possible scenarios. For example, it might be a sensor that has been removed (either intentionally or by mistake). It could also be a sensor that has fallen off, or perhaps you're standing by a table or area that you can't identify within the system.
In all cases, you must start by identifying the sensor.Once the sensor has been identified, you need to determine whether it should be taken out of service, or if it has been removed or has fallen off by mistake and therefore needs to be reinstalled.