Pressure sensing quartz crystal sensor RKMA-P

Pressure sensing quartz crystal sensor RKMA-P. The RKMA-P is designed to work in composition of precision electronic transducers, pressure gauges and pressure controllers with a frequency or digital output signal as a converter of current values of pressure to frequency.

Applications

The RKMA-P is designed to work in composition of precision electronic transducers, pressure gauges and pressure controllers with a frequency or digital output signal as a converter of current values of pressure to frequency.

Device

RKMA-R - manometric sensor, consists of a membrane 3, on which a force-sensitive piezoresonance element in the form of a dual tuning fork of flexural vibrations is rigidly fixed. The piezoelectric element is located in an evacuated cavity formed by the gasket 2 and the cover of the sensor 1. All the details of the resonator are made of single-crystal quartz. Under the action of sensor, the membrane bends, stretching or compressing the force-sensitive piezoelectric element, and the RKMA-P resonance frequency changes due to the pressure-acting conversion function.

Features

• High resolution and accuracy;
• Long term quartz crystal stability;
• Radiation resistance;
• Low temperature dependence reproducible in a wide range of operating temperatures (-60…+80 °C);
• Low power consumption;
• Suitable for precision pressure equipment

A number of RKMA-R, differing in design features and ranges of working pressure is produced.

Electrical characteristics (at normal climatic conditions) / Operating conditions

* the coefficients of the function are determined by individual graduation, with connecting RKMA-P-1 (21, 3, 4) to the oscillator.

** when ordering, you must specify the desired operating temperature range.

Temperature sensing quartz crystal RKT206 may be used for compensation of a temperature deviation of RKMA-P.

Precision electronic transducers, pressure gauges and pressure controllers (with the ability to compensate for temperature error)  with an accuracy class up to 0.01 are developed and manufactured based on RKMA-R.

Inverse temperature-compensated conversion function: Р(Fp, T) = C₀ + C₁ × (T - T0) + C₂ × (T - T0)² + C₃ × (Fp - Fp0) + C₄ × (Fp - Fp0)² + C₅ × (Fp - Fp0) × (T - T0)

where  Fp is the current value of the frequency of the crystal PKMA-P-OS-21 (Hz);

       T is the current temperature value (°C);

       T0, Fp0, C₀, C₁, C₂, C₃, C₄, C₅ are the coefficients of the transformation function determined as a result of calibration.

External dimensions

There are 4 main versions of the quartz manometric absolute pressure sensors RKMA-R:

• RKMA-R-1 without rigid fixation, placed in a container;
• RKMA-R-21 light-sized version;
• RKMA-R-3 has a thermomechanical decoupling of the cover, which is glued to the surface of the sensor housing;
• RKMA-R-4 has a metal fitting through which the measured pressure is supplied.

UNITS: millimeters

RKMA-P-1	RKMA-P-3	RKMA-P-4	RKMA-P-21
1- Cover; 2- Gasket; 3- Membrane; 4- Contact pads.