Absolute pressure transmitters, also known as absolute pressure transducer,
and absolute pressure sensor.
Absolute pressure sensors and gauges produce readings, that are not influenced by atmospheric pressure.
Instruments such as altimeters and barometers display vacuum-referenced absolute pressure measurements.
What is absolute pressure transmitter?
Absolute pressure (AP) transmitter measure relative to perfect (full) vacuum pressure (absolute zero pressure)
Therefore, AP transmitters are not affected by fluctuations in the local atmospheric pressure.
All absolute pressure measurements are positive.
The letter ‘a’ or the abbreviation ‘abs’ in the unit of measure
(i.e., inH₂O(abs) or psia) indicates an absolute pressure measurement.
SMT3151AP Absolute Pressure Transmitter Features
Sensor Type : Industrial Pressure Transducers
Full function buttons on site
Pressure ranges 0 … 1 mbar up to 0 … 600 bar
Output/Span : 0 – 10 V, 0 – 5 V, 1 – 5 V, 10 mV/V, 4 – 20 mA, HART
Pressure Port/Fitting : 1/2 MNPT, 1/4 FNPT, 1/4 MNPT, 1/8 MNPT
Operating Temperature Range: -40 – 85 °C [ -40 – 185 °F ]
What is the absolute pressure?
Absolute pressure is referred to the vacuum of free space (zero pressure).
In practice, absolute piezoresistive pressure sensors measure the pressure relative to a high vacuum reference,
sealed behind its sensing diaphragm.
The vacuum has to be negligible compared to the pressure to be measured.
Sino-Instrument’s absolute pressure sensors offer ranges from 1 bar or even 700 mbar,
as well as barometric pressure ranges.
Most electronic pressure sensors measure gauge pressure ( Gauge Pressure Transmitter ),
based on the deformation of a diaphragm.
If the diaphragm is exposed to the process pressure on one side,
and vented on the other side (exposed to ambient pressure),
the deformation is reduced by the amount of ambient pressure.
This means a gauge pressure reading is actually the pressure difference,
between the process pressure and the atmospheric pressure.
With absolute pressure sensors,
the side of the sensor not in contact with the pressure media,
is exposed to an absolute vacuum chamber that is permanently sealed.
The deformation of the diaphragm is not impacted by atmospheric pressure,
because it uses the sealed vacuum as its reference and zero point.
Applications for Absolute Pressure Sensors
Absolute pressure sensors and absolute pressure gauges,
are typically found in applications,
that require the monitoring of industrial high-performance vacuum pumps.
For example, industrial packaging machines,
are used for vacuum packaging of medical products,
in a clean environment,
to ensure sanitary and bacteria-free delivery to hospitals and doctors.
In the food industry,
vacuum packaging is utilized,
when the highest level of vacuum possible is required to prevent oxygen,
from degrading perishable food,
thereby greatly extending the product’s flavor and shelf life.
Conventional pressure gauges and sensors,
which are affected by influences in the atmosphere,
are unable to monitor the high end of a vacuum.
Applications requiring true absolute pressure sensors and gauges,
can also be found in scientific laboratories, universities, the military,
and the aviation industry.
Sino-Instrument supplies Direct Mount Pressure / Absolute Pressure Transmitter.
Our SMT3151ap absolute pressure transmitters,made in China,
are our mian products, which are widely used in India, US, South Africa,
and other countries.
Contact us any time, if you need the quotation or technical support.