Delta OHM HD404ST Series - Low Pressure Transmitters

The series of HD404T transmitters is able to measure relative pressures with reference to the atmosphere or differential in the range:

• from 50 to 1000 Pa (from 0.2” H2O to 4” H2O) for the versions with analog output;
• 250 Pa / 1000 Pa / 100 mbar for the versions with RS485 Modbus‑RTU output.

The series uses 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, depending on the model, into a standard current analog output (4-20 mA) and a voltage analog output (0-10 V), or into a digital RS485 Modbus‑RTU output, which, then, can be transmitted over long distances with a high immunity to noise.

In the models with analog output it is possible to choose, via a dip switch, between two measurement ranges in order to select the optimal scale for each application.