One bucket may contain several devices. However, each device can be connected to only one bucket. 

It means that the device will be filling (sending data to) only one bucket, and that the device is able to read variables from only one bucket. To make the same variable available to different devices, it is recommended to connect more devices in the same bucket, or use scripts in the Analysis to copy certain variables from one bucket to another.

Note that when selecting variables in a dashboard or in the analysis, you will be requested to select the bucket and the device of origin that sent the variable. In case a bucket received data from different devices with the same variable name, it is easy to separate them by defining its origin. 

For example, Device01 and Device02 are sending both the variable ‘temperature’ to the bucket MySensors. To display the temperature from one specific device, just add the name of the device in the origin field.