The series of HD404T transmitters is able to measure relative pressures with reference to the atmosphere or differential in their range from 50 to 1000 Pa (0.2″ H2O to 5″ H2O). HD404T transmitters use a silicon “micro-machined” type sensor compensated in temperature that has an excellent linearity, repeatability and stability over time. The output signal from the sensor is amplified and converted into a standard analogical output in current (4-20mA) and in one in voltage (0-10V), which, then, can be transmitted over long distances with a high immunity to noise.
Also supplied with MODBUS (see leaflet)
In each model it’s possible to choose, via a dip switch, between two measurement ranges in order to select the optimum scale optimal for each application. Typical applications for HD404T series are:
Clean room monitoring
Air conditioning control
Usually the low pressure transmitters are susceptible to the guidance by which they are mounted. In HD404T series there is available a special auto-zero circuit, which periodically equalize the differential pressure at the input sensor and corrects
the offset; the transmitters, provided with this circuit, are insensitive to the mounting position. In addition, The circuit compensates autozero aging and the deviation of the zero of the sensor to temperature changes: virtually eliminates
maintenance. It’s available the (L) “display” option, in which the pressure is visualized on a display with 4 digits in the selected measurement unit.
The (SR) “square root” is especially useful if the transmitter is connected to a pitot tube, as the output is directly proportional to the speed of airflow.
The transmitters are ready to use and are supplied calibrated at 3 points by the manufacturer.