Relative pressure transmitter HD404T

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The HD404T series of Pressure Transmitters is able to measure relative pressures with respect to the atmosphere or differential pressures up to 1000 Pa. The transmitters use a temperature compensated “micromachined” silicon sensor which exhibits excellent linearity, repeatability and stability over time. The sensor signal is amplified and converted, depending on the model, into a standard analog output in current (4÷20 mA) or voltage (0÷10 V), or into a digital RS485 Modbus-RTU output, and can therefore be transmitted over long distances with high noise immunity. In the models with analog output it is possible to choose, using a dip switch, between two measurement ranges in order to select the optimal full scale for your application. An optional auto-zero circuit (AZ) periodically equalizes the differential pressure at the sensor inlet and corrects its offset; transmitters equipped with this circuit are insensitive to the mounting position. In addition, the auto-zero circuit compensates for the aging and zero drift of the sensor as the temperature varies, allowing maintenance to be reduced to a minimum. The display option (L) is available, where the pressure is shown on a 4-digit display in the chosen unit of measure. The “square root” (SR) version is useful if the transmitter is connected to a Pitot or Darcy tube, as the output is directly proportional to the speed of the air flow. The SR version with option L allows you to view on the display, in addition to the measured pressure, also the calculated speed of the air flow. It is possible to set the coefficient of the Pitot or Darcy tube used and the parameters for calculating the speed (temperature of the air flow,