Total Pressure Measurement in a Vacuum With Analog Signal Output.

Total Pressure Measurement

CMR capacitive transmitters are the perfect solution for total pressure measurement when the need is for highly accurate measurements that are independent of the type of gas in question. They are suitable for all applications in the pressure range from 1,100 to 1 · 10-5 mbar, and are characterized by their long service life. At the same time, they afford minimum zero drift and outstanding temperature stability. They are non-wearing, resistant to corrosive gases, insensitive to atmospheric pressure and do not require an additional shutoff valve. The integrated sensor shield affords increased protection against contamination.

Operating Principle

Our transmitters measure the deflection of the diaphragm in form of a change in electrical capacitance detected by the conductors that are vapor-deposited on the ceramic diaphragms. By varying the thicknesses (d) of the diaphragms it is possible to provide measurement ranges from 1,100 to 10-5 mbar. The thinnest diaphragms are barely as thick as a human hair (0.01 mm), and the measured deflections (S) are a mere 0.001 mm. In order to be able to reproducibly measure these small effects, the entire sensors in the CMR transmitters are of ceramic design, as this material has a very small coefficient of expansion.

This means that temperature changes have only a minimum influence on deflection of the diaphragm, which is not pressure-dependent. And ceramic also offers a further advantage over other materials: Even after being flooded with atmospheric pressure, the diaphragms quickly return to their initial position. There are no memory effects of the kind that are typical of metallic sensors. Which means: No long waits
until the transmitter is measuring accurately again.

Advantages

• Large variety of transmitters to cover the entire pressure range (5•10^-10 to 55,000 hPa)
• Compact design
• Easy integration
• Cost effective
• Integrated measurement connections
• Compact independent transmitter
• Output signal 0 – 10 V with integrated error signal

For further enquires please contact us on contact@scitek.com.au or on our contact page.