The Datatest Model 109 is a microprocessor based non-compliance opacity monitor for process, baghouse, combustion and OSHA applications. The micro controller provides excellent accuracy, reliability and stability with features such as push button calibration, path length correction and averaging. Alarms for pre-emission, over-emission, lamp out and blower out are displayed on the LCD with relay contacts . 0 - 5Vdc and 4-20 mA interfaces for instantaneous opacity plus as an option 0-5 Vdc and 4 - 20 mA interfaces for average opacity. RS232/422 serial ports are available. The standard control unit is panel mount or NEMA 4 wall mount. Available in a double pass (Model 109MPD) for spans of 5 feet or less or a single pass (Model 109MPS) for spans up to 35 feet.