... Voltage Meter, Ampere Meter1) 8-bit micro processor, 5 digit LED display, range up to 19999, sampling ... rate 2.5 times / second, high accuracy; 2) Optional ... Key lock function to avoid careless value change;5) Power supply 85-265V AC/DC, suitable ... Some models have RS485 communication function, users can read different value on PC, including measuring value, alarm ...