Products Catalog

Specification

HD 9408T BARO, HD 9408TR BARO
and HD 9908T BARO are analog output electronic
barometers. The piezoresistive sensor gives extremely accurate and stable measurement
of 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 to use as they have been factory calibrated. An offset adjustment
potentiometer is available for station elevation.
HD9408T BARO requires a DC supply voltage, its low power consumption (< 4 mA)
makes it suitable for portable and remote battery or solar powered applications. It is
available in different kinds of analog output: 0-1 Vdc, 0-5 Vdc (1-5 Vdc, 1-6 Vdc on
request) or 4-20 mA (two wires).
HD 9408TR BARO offers higher temperature performance: the internal circuitry allows
the sensor to work at constant temperature so that it achieves accurate temperature
compensation over the whole range from -40°C to +60°C.
HD 9408TR BARO requires a continuous DC supply voltage. It is available in different
output versions: 0÷1 Vdc, 0÷5 Vdc (1÷5 Vdc, 1÷6 Vdc on request).
HD 9908T BARO, is a barometric transmitter equipped with a 3 ½ digi display (1 mbar
resolution) showing pressure measurements it has a 0÷20 mA, 4÷20 mA, 0÷1 V and 0÷5
V (0÷10 V on request) analog output confi gurable by the customer and an ON/OFF relay
with programmable alarm threshold.
HD 9908T BARO requires a 24 Vac (or 220 Vac on request) power supply.
HD 9408T BARO, HD 9408TR BARO and HD 9908T BARO are low cost and high
-performance solutions for meteorological applications, environmental monitoring
systems, weather and environmental data logging, barometric pressure compensation
for internal combustion engine performance, cleanroom barometric pressure
compensation, automotive emission test.
HOUSING AND INSTALLATION
In all models the sensor and the electronics are housed in a sturdy MACROLON box
(degree of protection IP67). When the lid is opened, holes allow fi xing the base of the
transmitter to a panel or surface. The precision of measurement does not depend on the
position of the transmitter. However it is advisable to fi t the transmitter in such a way
that the sensor is facing downwards so as to minimize the accumulation of dust or dirt on the fi lter.
If the transmitter is installed in an outdoor location, it is recommended to use a pressure
port which minimizes the errors caused by the wind flow.
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.
- Power 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 perform as shown in table 1.
NOTE: the ALARM led on indicates that the relay is energized and the contact is
closed.
- Once the installation is complete, make sure that the cover is perfectly closed;
the same applies to the grommets.
HD9408PS 50
STATIC PORT FOR BAROMETRIC MEASUREMENTS
[ GB
] GENERAL DESCRIPTION
The measurement of barometric pressure in free fi eld can
give wrong values, of hundreds
of pascal, because of wind fl uctuation and direction. The HD9408PS 50 static port for
barometric measurements minimizes such errors, because, besides working as a fi lter
(brake) against the wind dynamic pressures, it allows the barometer to work properly,
even in the presence of snow or ice, as well as to conform to the WMO recommendations
(World Meteorology Organization). The materials in are UV-resistant and can operate in
the temperature range between –40°C and +80°C.
INSTALLATION AND CONNECTION
The instrument is easy to install and it has to be placed far from buildings, trees or
any other source that might disturb the flow of the wind. The HD9408PS 56 mounting
bracket and three M5x16 Stainless Steel screws are available to fi x the port properly.
The connection of the static port to the barometer, i.e. either to a HD9408T or to a HD9408TR, is carried out through the HV55 special tube (inside Ø : 3mm, outside Ø
: 6mm), which is resistant to climate changes and UV. Maintenance and cleaning are
very simple. Plastic parts are in LURAN S777K, manufactured by BASF. It is strongly
suggested to use non-aggressive cleaners, compatible with the plastic material.
TECHNICAL SPECIFICATIONS
According to the WMO recommendations, the allowed measurement deviation at a
20meters/second wind speed is 0.3mbar, corresponding to 300 Pascal. The HD9408PS
50 static port for barometric measurements complies with this value. The following
tables show the values obtained by the tests made in the wind tunnel.
ORDERING CODES
HD9408T BARO Barometric, transmitter output 0÷1Vdc, measuring range
800÷1100mbar. On request output: 0÷5Vdc, 1÷5Vdc, 1÷6Vdc, 4÷20mA, working
temperature -30°C ÷ +60°C.
HD9408TR BARO Barometric transmitter, 800÷1100mbar, output 0÷1Vdc. On request
output 0÷5Vdc, 1÷5Vdc. Temperature working range –40°C ÷ +60°C, sensor
heated.
HD9908T BARO Barometric transmitter, 800÷1100mbar with LCD indication. Outputs:
0÷20mA, 4÷20mA, 0÷1Vdc, 0÷5Vdc. Working temperature -20°C ÷ +60°C.
HD9408PS 50K Kit composed of static port, mast mounting bracket and HV55 tube
HD9408PS 50 Static port for barometric measurements equipped with HV55 tube
HD9408PS 56 Mounting bracket for static port, barometer and mast fi tting
HV55 Silicone tube resistant to UV and temperature, inside Ø : 3mm, outside Ø : 6mm,
L=400mm