Microprocessor-based trip device with optional functions and selection process of said functions

Claim 1

A microprocessor-based trip device for an electrical circuit breaker comprising: current detection means for generating analog signals representative of currents flowing in conductors protected by the circuit breaker; analog to digital conversion means to which the analog signals are applied for converting said analog signals to digital signals; a microprocessor-based digital processing unit to which the digital signals are applied to perform at least standard long delay and/or short delay tripping functions and which generates a circuit breaker tripping order when present tripping parameters are exceeded, said unit comprising a keypad, display means, a random-access memory and a read-only memory connected to the microprocessor, the read-only memory comprising a plurality of subroutines corresponding to the standard functions and to a plurality of optional functions of the trip device; circuit breaker tripping means actuated by the tripping order; and optional function selection means for enabling certain optional functions, said option function selection means comprising said keypad and an electrically erasable programmable read only memory (EEPROM); wherein said keypad is utilized by an operator to select optional functional subroutines from said ROM and command storage of said selection in said EEPROM and to enter the tripping parameters.