Several modes for pressure measurement are shown in the table below.

The Differential pressure is the pressure between two isolated points, the gauge and the compound pressures are the pressure referenced to atmospheric pressure and the absolute pressure is the pressure referenced to the perfect vacuum.
A sensitive element called a diaphragm in the pressure transducer will displace when the pressure is applied, so that the four strain gauges on the element can detect the displacement as its electrical resistant changes by the applied pressure.
The mechanism of the pressure transducer is shown in the picture below.

In generally the tensional force is generated on centre of the diaphragm and the compression force is also generated on around of the diaphragm when the pressure is applied to the pressure transducer. The electrical resistance increases by tensioning the strain gauges and decreases by compressing the strain gauges so that the output from the strain gauges is obtained by arranging a Wheatstone bridge circuit to these strain gauges.
The pressure transducer for the model PEN-33 employs diffused strain gauges and the pressure is applied to the surface of the silicone base plate and the other strain gauges are bonded on the back of this plate.
The model PE-33 provides good accuracy with fast response and temperature independence.
The silicone diaphragm for this pressure transducer has a same property to the glass plate one so that it can be applied to the corrosion fluid. The pressure from liquid is primarily applied to a stainless steel diaphragm in order to keep the reliability of pressure transducer due to small droplets on the strain gauges and the pressure is transferred to the silicone diaphragm via silicone oil for the type(G), and (A).
The silicon diaphragm have a property similar to glass plate so that it have good corrosion resistance, but small water drops on the gauge may cause some problems of the reliability when liquid are used, therefore both the gauge and absolute sensors firstly receive the pressure on the stainless steel diaphragm and relay the pressure using with silicon oil to the silicon diaphragm to avoid the problem above.
The output signal from the strain gauges is small so the signal is amplified to 10VDC in order to display the pressure as the voltage signal.
The raw electrical output is so low voltage that it is amplified to 10V and showed on the digital indicator.
One of the most important factors for pressure gauge is to keep the long-term accuracy.
The graph below shows the test results by applying the pressure repeatedly in one million times to model PE-33 pressure gauge.

The results show the errors less than +/-3% but these are reduced by the periodic calibration with a primary instrument.
Sokken provides accurate pressure gauges over wide ranges(near atmospheric to 400MPa) by calibrating with a dead weight tester in traceable by JCSS.

Features

• Reasonable price with high accuracy(+/-0.3% F.S.).
• Fast response -  <1ms(T_90%) at the pressure port.
• Corrosion resistant stainless steel diaphragm for the transducers type -G, -A and -C.
• Allow to apply the pressure exceed 4 times of the rated range for engine applications.

Specifications

Applications

• Intake, Exhaust, Radiator, Hydraulic system, Crank case, Differential Pressure in intake air flow and Transmission pressure for IC engines.

Related products

PZ-77 series (+/-0.1%) differential pressure gauge with high accuracy