A microprocessor-based portable test equipment for electricity network

A microprocessor-based multi function test equipment measuring the power system parameters such as the line voltage amplitude, line current amplitude, load power, power factor and the line frequency is reported. In addition to measuring and displaying these parameters cyclically, the instrument also records the instants where the line voltage amplitude and the line frequency cross the limits of the specified range. These limits, called as fault tolerant limits, are programmable with the system. Depending upon the requirements of the usage, the user could set the limits by using a keyboard interfaced to the system. The instrument records the fault occurring instants together with the time periods over which the fault remained. The system also runs a software controlled digital clock. The measured parameters and the time are displayed alternately at regular time intervals of two seconds. An interrupt to the microprocessor displays the fault sequences registered