Vaisala PTB330 - Manual (Page 16)

USER'S GUIDE____________________________________________________________________
14 __________________________________________________________________ M210855EN-D
Basic Features and Options
- Applicable in industrial and meteorological areas
- Calculated aviation related output quantities: QFE and QNH
- 1 ... 3 BARO-1 barometer modules (sensors)
- Barometer mounting accessories for multiple installation purposes
- Service port for MI70 Link Interface Software or PC
- Four module slots
- IP 65 housing
- Screw terminal, optional M12 connector or D-9 connector
- Optional graphical display showing the measurement trends of the
quantities chosen by the user
- Optional modules: power supply module, RS-485 module, analog
output module, and relay module
- Optional USB cable for service use or data transfer
Pressure Measurement
The PTB330 series barometers use a BAROCAP
®
silicon capacitive
absolute pressure sensor developed by Vaisala for barometric pressure
measurement applications. The BAROCAP
®
sensor has excellent
hysteresis and repeatability characteristics, low temperature
dependence, and a very good long-term stability. The BAROCAP
®
sensor is very robust and resistant to mechanical and thermal shocks.
The measurement principle of the PTB330 series digital barometers is
based on an advanced RC oscillator and reference capacitors against
which the capacitive pressure sensor is continuously measured. The
microprocessor of the barometer performs compensation for pressure
linearity and temperature dependence.
Each barometer module in PTB330 has its own adjustment
coefficients for different reference pressures across the entire
temperature range. This achieves the best possible accuracy needed in
barometric pressure measurements.