HD9408.3B is a barometric transmitter that uses a piezoresistive high accuracy andtemperature-compensated sensor. It allows measuring the atmospheric pressure withextreme accuracy, time stability, excellent repeatability, low hysteresis and excellenttemperature behavior.Pressure measuring ranges:

• 0…1350 hPa (HD9408.3B.1 and HD9408.3B.2 digital outputs)
• 100…1350 hPa (HD9408.3B.3 SDI-12 output)
• 500...1200 hPa (HD9408.3B.1 and HD9408.3B.2 analog outputs)

The superior performances are obtained thanks to the employment of a piezoresistive Silicon sensor that integrates both a pressure sensitive as well as a temperature sensitiveelement. The measurement of pressure and temperature are processed by a microprocessor to obtain an output signal that is compensated over the transmitter’s whole, widetemperature operating range: -40…+85°C.The sensor is factory calibrated at several points at different temperatures in therange of use.

The transmitter is available in three versions which differ in the output type:

• HD9408.3B.1: configurable 0…5 V or 1…5 V analogue voltage output and digital RS232, RS422 or RS485 output. Standard MODBUS-RTU and NMEA 0183protocols.
• HD9408.3B.2: active configurable 0…20 mA or 4…20 mA current output anddigital RS232, RS422 or RS485 output. Standard MODBUS-RTU and NMEA 0183protocols.
• HD9408.3B.3: digital SDI-12 output, compatible with version 1.3 of the protocol.

The digital output enables the transmission of the measurements over long distancesand connects the transmitter to sensor networks.The pressure measured and transmitted with MODBUS RTU and SDI-12 protocols canbe expressed in different user-selectable measuring units.The watertight housing with IP 67 protection degree allows the use of the instrumenteven in harsh environments.The instrument is particularly suitable for meteorological applications (AWOS - Automated Weather Observing Systems), environmental monitoring systems, meteorological and environmental data logging, measurement laboratories, atmospheric pressurecompensation in the performance of internal combustion engines, barometric pressurecompensation in clean rooms, vehicle emission test.Its low power consumption makes it ideal for remote acquisition systems such as automatic weather stations powered by solar cells.