These highly versatile digital instruments enable continuous and comprehensive monitoring of fixed site or mobile AC and DC electrical systems. They provide quick easy-to-read and accurate information on all important aspects of electrical system status: voltage, current, power consumed, power available and AC frequency. In addition, abnormal system conditions such as high/low voltage trigger user-adjustable alarms. All read-outs and programming of these multiple functions are easily controlled via touch-pads on the instrument face. LCD displays are easily read in bright sunlight and feature five level adjustable red back-lighting for conservation of night vision. High/low voltage and frequency alarms are standard, and DC monitors are NMEA 0183 compatible. Typical accuracy is +/- 1%.