360° Format: For years a 360° potentiometer has been the standard for measuring wind direction. Because the resistance element of the potentiometer is roughly 358°, there is a "dead area" or "slot" of approximately 2°. This opening in the pot is customarily oriented to the north. The 360° format is extremely well suited to applications where a display indicator is used, either alone or with analog recording instrumentation. Its disadvantage is that when the wind is from the north readings will vary between maximum to minimum output as the wiper in the pot goes back and forth across the slot, thereby causing a pen trace across the full width of an E-A recorder or presenting numerous other complications for computer data logging.
540° Format: In recent years, a new configuration has been used quite successfully. Two potentiometers are joined together with wipers in the pots 180° from each other, thus providing a 540° uninterrupted display. This convention of dual potentiometers has greatly minimized the problems encountered in 360° displays. The signal conditioning provides automatic switching between the two pots.