This product is a HEMS controller for a low voltage Smart meter. The main feature is to acquire its Import and Export energy data of the low voltage Smart meter via its Utility’s B-route service. With the NB-IoT/LTE-M mobile connection, Its energy consumptions or power quality information of a Sub meter embedded the HEMS controller, its Import & Export energy of the low voltage Smart meter, and its environmental data of the system like a Solar power system can be consolidated and sent to a cloud server periodically. All transmitting data have been encrypted by AES-GCM-128 algorithm and protected by dynamic security key exchange process. Its modular design of the Sub meter provides the maximum flexibility, and it allows the Sub-meter to be expandable with different customized features in the future.