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.