PRESSURE MANOMETER

Pressure Manometers use many different sensing technologies. Mechanical deflection devices such as diaphragms, Bourdon tubes or bellows consist of an elastic or flexible element that is deflected mechanically by a change in pressure. Sealed pistons or cylinders are also available. Strain gauges are bonded to a larger structure that deforms as pressure changes. Piezo resistive devices sense shifts of electrical charges within a resistor. Piezoelectric pressure instruments measure dynamic and quasi-static pressures.

Their common modes of operation are charge mode, which generates a high-impedance charge output; and voltage mode, which uses an amplifier to convert the high-impedance charge into a low-impedance output voltage.

Thin film devices consist of an extremely thin layer of material, usually titanium nitride or polysilicon, deposited on a substrate. Pressure instruments that use micro electro mechanical systems (MEMS), variable capacitance, and vibrating elements are commonly available.

Pressure Manometers are capable of performing various pressure measurements and displaying amounts in different units. Absolute pressure is a pressure measurement that is relative to a perfect vacuum. Typically, vacuum pressures are lower than the atmospheric pressure. Gage pressure, the most common type of pressure measurement, is relative to the local atmospheric pressure. By contrast, sealed gauge pressure is relative to one atmosphere of pressure (oz) at sea level. Differential pressure reflects the difference between two input pressures.

Compound pressure instruments can display both positive and negative pressures. Some pressure instruments display values in pounds per square inch (PSI), kilo pascals, bars or millibars, inches or centimetre of mercury, or inches or feet of water. Other devices display measurements in ounces per square inch or kilograms per square centimetre.

TYPE OF PRESSURE MANOMETER

Pressure Manometers can produce several types of electrical signals, including analog voltage and analog current. These output signals can be encoded via amplitude modulation (AM), frequency modulation (FM), or some other modulation scheme such as sine wave or pulse train. Common communication protocols include Ethernet, DeviceNet, FOUNDATION Fieldbus, and highway addressable remote transmission (HART). HART is a registered trademark of the HART Communication Foundation. Several serial and parallel interfaces for pressure instruments are available. RS232 and RS485 are serial, digital protocols.

Parallel protocols include the general-purpose interface bus (GPIB), a standard which is also known as IEEE 488. Some pressure instruments output TTL signals. Others provide outputs that change the state of a switch or alarm.

PRESSURE MANOMETER SPECIFICATIONS

• Backlit LCD Dual Display

• Low Battery Indication

• Under Range and Over Range Indication

• Fast Response Time

• Battery Operated.

• Measuring Range: 0 – 5 PSI

• It measures in various units like inH2O, PSI, bar, mbar, kPa, inHg, mmHg, OZin2, ftH2O, cmH2O, kgcm2.

• With RS-232 PC Interface Facility

• High Accuracy of 0.3%