Siemens 546-00437B LAB EL ACT, AN/FP, ACT ONLYSiemens 546 00437B LAB EL ACT, AN FP, ACT ONLYThe Fume Hood Controller is an integral part of the APOGEE Automation System. The controller is a proven, patented stand alone Direct Digital Control (DDC) system for Variable Air Volume (VAV) control of laboratory fume hoods. The controller maintains constant face velocity as the fume hood sash is raised and lowered. An Operator Display Panel provides the fume hood user with the face velocity readout,