Voltcraft dl 151an anemometer data logger voltcraft dl 151an the voltcraft dl 151an anemometer data logger is a compact data logger in a usb drive enclosure for monitoring and recording wind speed the logging interval is adjustable from 2s to 24hrs by software on the computer the internal lithium battery makes for a long operating period it is able to store 32 000 measure values the recorded data can be read and processed with the enclosed measuring software which has a graphing function