HD 9408 – Barometric Transmitter
HD 9408T BARO, HD 9408TR BARO and HD 9908T BARO are analog output electronic barometers. They use a piezoresistive sensor element which gives extremely accurate and stable measurement of the atmospheric pressure and assures excellent repeatability, low hysteresis and very good temperature stability. The output signal of the sensor is conditioned to provide a voltage or a current output linearly proportional to the barometric pressure.
The transmitters are ready as they have been calibrated at the factory. A zero adjustments potentiometer is available for offset to station elevation..
CONNECTION DIAGRAM AND OPERATION
– Make the power connections for the HD 9908T BARO.
– Make the connections for the relay output, the relay contact is free.
– Select the analog output 0÷20 mA, 4÷20 mA, 0÷1 V, 0÷5 V by means of the jumper.
– Switch on the instrument, press the PUSH button and turn the SET trimmer to set the desired threshold value between 800 and 1100 mbar; the set value is shown on the LCD display.
– Using the trimmer, set the desired HYS (=hysteresis) value between 5 and 50 mbar.
– The instrument will now indicate the barometric pressure; HI led, LO led or ALARM led
and ALARM relay will switch on if one the following cases occurs (see table 1).
NOTE: the ALARM led comes on to indicate that the relay is energized and the contact is closed.
– Once installation is completed, check that the cover is tightly closed; the same applies to the grommets.