A relay and metering test instrument includes an application processor circuitry to control functional operation of the relay and metering test instrument. The application processor circuitry may receive a user selected source code state program, and operational parameters input by the user. The application processor circuitry may compile the source code state program and the operational parameters into a test routine for storage in a memory circuitry with other test routines. The relay and metering instrument may also include a real time processor circuitry and an input/output processor circuitry. The real time processor circuitry may selectively and independently execute the test routine or one of the other test routines to perform one or more respective testing stages. The input/output processor circuitry may cooperatively operate with the real time processor circuitry to output test signals and monitor for receipt of input test signals according to execution of the test routine.