Abstract: A ground fault interrupter, operable in a measurement state, is employed with a DC circuit having a DC power source and a load. The DC source supplies DC current to the load along a supply current path and receives DC current from the load along a return current path. The ground fault interrupter comprises a first resistance in series with the supply current path, a second resistance in series with the return current path, and a current interrupter disposed in series with one of the current paths. The current interruptor interrupts the one of the current paths in response to actuation of the current interrupter. The ground fault interrupter further includes a measurement unit for measuring voltage drops across the respective first and second resistances during the measurement state, obtaining a measurement value using a difference between the voltage drops, and comparing the measurement value to a predetermined threshold.

Abstract: An automated vascular testing apparatus includes capillary blood flow sensors and blood pressure detection sensors to detect data regarding the blood flow of a patient. Error detection apparatus insures that the blood data sensors are properly connected and that the output signals therefrom are reliable and provide an adequate basis for measurement. A controller monitors the output signals from the sensors and manages the overall operation of the automated testing procedures. The controller memory temporarily stores the output signals from the blood data sensors, along with other miscellaneous data. A video display presents instructions, data, and conclusions based on accepted medical theories to the operator, while a printer optionally reproduces these data in hard copy form.