Beta: Meter transactions are time-limited and digitally signed references of readings, which can be billed separately. They are ideal for e-mobility charging processes.
Application: e-charging stations
The smart-me meter (version 2) is installed in the charging station. The meter’s digital output is connected directly to the charge controller and can thus start and stop charging. The meter display and the calibration mark are visible on the front of the charging station.
Sequence: charging process
1. The charging process is started (e.g. using an app). The ‘Start transaction’ command is sent to the meter. It starts a new transaction and activates the charging station. The display switches from the scrolling display of meter readings to the transaction display. Consumption for the transaction starts at 0 kWh and counts upwards according to consumption.
2. On the display the user sees the current charging capacity and the energy already consumed.
3. The charging process is terminated (e.g. using the app). The ‘End transaction’ command is sent to the meter. It ends the transaction, signs it and sends the transaction data and the digital signature to the cloud. Completed status for the charging process is indicated to the user on the display for five minutes.
Checking the charging process afterwards
Customers can check how much energy has been consumed at any time once the charging process is complete. To do this, all they have to do is select the corresponding transaction in the app or online, and check it with the meter’s public key. All public keys for smart-me meters are publicly available in the smart-me cloud (or using API).
The transaction data can easily be verified online with the signature and the public key.