The MP-V and RP-V controllers use a digital pressure sensor to measure the air velocity pressure signal from the velocity probe in the inlet of the VAV box. The measured value is used by the controller to position the VAV damper actuator for the required air flow.
The microflow of the sensor is so low that the sensor does not introduce an error (reduction) of the pressure from the velocity probe seen on the test/balance taps. This enables local digital manometer measurement of the velociy pressure when needed to verify flow readings.
The sensor does not require maintenance.
The sensor is factory-calibrated and requires a minimum of field adjustments. Field air balance calibration is typically only needed when adjusting for anomalies and inaccuracies introduced from the local duct and air flow situations.
The air flow sensor type differs between different MP-V hardware versions. The different sensor types differ significantly in terms of VAV air flow control range, especially at low flow. For more information, see Differences Between MP-V Hardware Versions .