Patent ID: 8880366

Claim:
A modular energy meter, comprising: a two-part housing comprising a cover and a lower shell, said cover and lower shell being detachably connectable to each other to define a sealed, access-protected portion and a non-sealed portion; and a window provided in said cover, said window forming an interface compliant with IEC 62056-21 for remote reading of an energy measurement or a counting value; wherein an internal module comprising at least a counter module and a terminal module is arranged in the sealed, access-protected portion of the housing, wherein an external module comprising at least an extension module is arranged in the non-sealed portion of the housing, wherein at least one optical interface is arranged in the internal module and at least one associated optical interface is arranged in the external module, said optical interfaces cooperating to permit communication between the internal module and the external module, and wherein the modular energy meter further comprises a reflector arranged between said optical interfaces, said reflector interrupting an optical path between said optical interfaces upon opening of the sealed, access-protected portion thereby permitting detection of the opening of the sealed, access-protected portion.