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
Parameters | Specifications and remarks | Units | ||||
Electrical characteristics |
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Model of the sensor |
RKMA-P-1 |
RKMA-P-3 |
RKMA-P-4 |
RKMA-P-21 |
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Frequency Range, fO |
40.000…48.000 |
kHz |
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Series resistance typ./max., RS |
120/ 200 |
150/ 250 |
kOhm |
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Drive level max., DL |
4.0 |
µW |
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Insulation resistance min., IR |
400 |
MOhm |
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Motional characteristics |
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Strait: F(P)=fO +A1*P +A2*P2+ A3*P3, where: F(P) – sensors’s frequency at current value of pressure P (Hz), Inverse: P(F)=BO +B1 x (F-F0) +B2 x (F-F0)2+ B3 x (F-F0)3 where: P(F) – pressure value corresponding to the current frequency of the sensor F(MPa), F0, B0, B1, B2, B3 – coefficients.* |
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Overalls |
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Operating Temperature, TOPR (typ/max) |
-60…+80 / -196…+180** |
°C |
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Temperature accuracy in the working temperature interval at P=0.1 MPa, no more |
± 20 |
Hz |
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Resolution |
0.005 (0.1) |
Hz(ppm) |
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Aging first year/10 years max |
± 15 / ± 40 |
ppm |
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Vibration Resistance (vibration from 10 to 2000 Hz with acceleration 5g during 8 houers), DF/F0 |
±5 max. |
ppm |
* 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. |
Working pressure intervals |
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The upper limit of the interval of working absolute pressure P |
Unit |
Sensitivity (linear coefficient) A1 ± 5...20% FS) |
Units |
Overall dimensions, no more |
Units |
RКМА-0.1-1 (3;4) |
0.1 |
MPa |
22000 |
Hz/MPa |
26 х 24 х 4.0 (6.0) |
mm |
RКМА-0.25-1 (3;4) |
0.25 |
10000 |
26 х 24 х 4.2 (6.2) |
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RКМА-0.4-1 (3;4) |
0.4 |
7800 |
26 х 24 х 4.3 (6.3) |
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RКМА-0.6-1 (3;4) |
0.6 |
2800 |
26 х 24 х 4.6 (6.6) |
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RКМА-1.0-1 (3;4) |
1.0 |
2100 |
26 х 24 x4.1 (6.1) |
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RКМА-1.6-1 (3) |
1.6 |
1100 |
26 х 24 х 4.4 (6.4) |
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RКМА-2.5-1 (3) |
2.5 |
1000 |
26 х 24 x4.6 (6.6) |
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RКМА-4.0-1 (3) |
4.0 |
500 |
26 х 24 x4.8 (6.75) |
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RКМА-6.0-1 (3) |
6.0 |
300 |
26 х 24 х 6.1 (8.1) |
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RКМА-10.0-1 (3) |
10.0 |
160 |
26 х 24 х 5.3 (7.3) |
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RКМА-16.0-1 (3) |
16.0 |
130 |
26 х 24 х 5.7 (7.7) |
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RКМА-0.1-21 |
0.1 |
20800 |
ø15 х 1.25 |
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RКМА-0.16-21 |
0.2 |
20800 |
ø15 х 1.8 |
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RКМА-0.25-21 |
0.25 |
15000 |
ø15 х 1.85 |
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RКМА-0.4-21 |
0.4 |
6000 |
ø15 х 1.95 |
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RКМА-0.6-21 |
0.6 |
3800 |
ø15 х 2.25 |
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RКМА-1.0-21 |
1.6 |
200 |
ø15 х 2.35 |