Bidirectional Mass Flow Control alicat.com/mcd Series Overview Alicat Scientific MCD-Series digital mass flow controllers precisely and rapidly control the mass flow rate, volumetric flow rate and pressure of process gases in two flow directions via customized high-speed proportional control valves. The dual-valve design pairs a dedicated inlet valve with a dedicated exhaust valve, allowing a single MCD to control upstream and downstream flows, as well as positive pressure or backpressure in both open and closed systems. At the heart of Alicat’s MCD-Series mass flow controllers is a patented, internally compensated, laminar differential pressure measurement technology that yields linear results over a very wide flow range. This produces volumetric and mass flow data that is fully compensated for changes in pressure and temperature and corrected for the user’s STP. All mass flow instruments come with NIST-traceable calibration and generous customer support, including free technical phone support, prompt recalibration service and a lifetime warranty. Alicat MCD-Series mass flow controllers feature large integrated displays with user-accessible setpoint control and PID valve tuning without need for a computer. The MCD Series comes with 30 selectable gas calibrations and both analog and RS-232 digital communications. Extensive customizations are available, including Class 1, Div 2 CSA/ATEX ratings for use in hazardous environments. The series is also available with corrosion-resistant wetted materials (MCDS Series) or low pressure drop (MCDW Series). Applications MCD-Series bidirectional mass flow controllers are used in a variety of industries, from scientific research and gas analysis to leak testing and environmental monitoring. Dual valves, multi-variable measurement and control functionality, multiple gas calibrations and a 200:1 turndown ratio allow an MCD to be used as a universal control element, replacing several application-specific devices. Available 0.4% accuracy + 0.2% full-scale repeatability and <100 ms control response times ensure top performance of gas flow processes. The MCD Series is available in full-scale mass flow rates from -0.5/+0.5 sccm to -3000/+3000 slpm.

Technical Data for Alicat MCD and MCRD Dual Valve Mass Flow Controllers 0 – 0.5 sccm Full Scale through 0 – 3000 slpm Full Scale Standard Specifications (Contact Alicat for available options.) Performance Accuracy for Bidirectional Controllers at calibration conditions after tare Repeatability MCD Mass Flow Controller ± (0.8% of reading + 0.2% of total span from positive full scale to negative full scale) ± 0.2% Full Scale Zero Shift and Span Shift 0.02% Full Scale / ºCelsius / Atm Operating Range / Turndown Ratio -100% to 100% Full Scale / 200:1 Turndown Maximum Controllable Flow Rate Typical...