Electro-Sensors SG1000D Valve Position Monitor is a complete position monitoring system housed in a compact and rugged explosionproof NEMA 4X enclosure. It is an encoder-based position sensor providing a 4-20 mA output and is used to measure a rotary process such as a valve position having a clockwise or counter-clockwise rotary movement. The SG1000D works on rotary processes having a full-scale sweep as small as 15 degrees (fully-closed to fully-open), up through those having a full-scale sweep as large as 359 degrees.