DETECTION METHOD OF EVENT OF UNAUTHORISED ACCESS TO ELECTRIC POWER MEASUREMENT AND COUNTING MEANS Russian patent published in 2013 - IPC G01R1/20 

FIELD: measurement equipment.

SUBSTANCE: detection method of event of unauthorised access to electric power measurement and counting means consists in the fact that every time the command has been received through interface, microcontroller shapes a unique check code, the value of which shall be constant till actuation of instrument opening sensor, or till the next command is received. Value of check code is stored to energy-independent memory of microcontroller, which is protected against being read, and displayed on the indicator display. After actuation of the instrument opening sensor the value of check code will be equal to zero. After the next command has been received, a new value of check code is shaped randomly, and it differs from the previous one.

EFFECT: method provides impossibility of concealment of instrument opening event at actuation of the opening sensor; electric power counting means have more reliable protection.