DIFFERENTIAL PRESSURE SENSING QUARTZ CRYSTAL RESONATOR BLOCK
BRKM-P
APPLICATIONS
BRKM-P is a quartz crystal resonator assembly, which consists of a measuring and a
reference quartz crystal, both packaged in a rectangular enclosure. The resonance frequency
varies with pressure-induced stress. BRKM-P is designed as a component for precision
electronic differential pressure transducers, manometers and controllers with a frequency
output for conversion of absolute pressure or differential pressure to frequency.
-
-
-
-
-
High resolution and accuracy
Long term quartz crystal stability
Wide temperature range (-55…+80 °C)
Low power consumption
Suitable for precision pressure equipment
FEATURES
In gauges of differential pressure BRKM-P is used to convert a pressure difference to a differential frequency output signal
fout =f
MEASURING
– f
REFERENCE
. An absolute pressure ( or differential pressure) P
1
is applied to diaphragm (1), while the absolute atmospheric
pressure (basic pressure)
Р
2
acts on diaphragm (3) (see drawing below), which stresses the reference resonator through the metal pipe (6).
One end of the connecting pipe is attached to an outlet of the quartz block, and the second one to an internal cavity of the case of the gauge
(5) where BRKM-P is subjected to the pressure
Р
1
. The internal cavity of the gauge is usually filled up by oil.
ELECTRICAL CHARACTERISTICS (at normal climatic conditions) / OPERATING CONDITIONS
PARAMETERS
Frequency Range, f
O
Resonance Resistance typ./max., R
r
Drive Level max., D
L
Insulation Resistance min.
SPECIFICATIONS AND REMARKS
Electrical characteristics
32.000…48.000
200 / 250
3.0
400
Motional characteristics
UNITS
kHz
kΩ
µW
MΩ
f(P)=f
O
+A
1
*P +A
2
*P + A
3
*P
where: f(P) – crystal frequency at pressure P (Hz),
f
O
– crystal’s frequency(in Hz) at zero value of pressure P,
A
1
– Linear coefficient = Sensitivity
A
2
, A
3
– Second and the third order coefficients*. Nonlinearity less than 0.4% FS.
Operation conditions
Model
Pressure Range
UNIT
Sensitivity (Linear Coefficient A
1
)
measuring crystal
reference crystal
7959
±
5…20%FS
3367
±
5…20%FS
1235
±
5…20%FS
304
±
5…20%FS
127
±
5…20%FS
Overall Dimensions /
Weight
Hz/MPa
25 x 23 x 4.5 / 6.0
Hz/MPa
25 x 23 x 5.1 / 7.0
Hz/MPa
25 x 23 x 7.0 / 9.5
Hz/MPa
25 x 23 x 10.4 / 17.0
Hz/MPa
25 x 23 x 12.2 / 18.5
0.1…25.0
79.98…106.64
UNIT
UNIT
mm / g
mm / g
mm / g
mm / g
mm / g
MPa
kPa
%
°C
°C
%
%
ppm
%
%
ppm
2
3
BRKM-0.16
0 – 0.16
MPa
BRKM-0.5
0 – 0.50
MPa
BRKM-1.5
0 – 1.50
MPa
BRKM-6.0
0 – 6.00
MPa
BRKM-16.0
0 – 16.00
MPa
Pressure Range, P
Pressure range of Reference Crystal
Variation of frequency difference over any 10K within the operating
< 0.1
temperature range
Operating temperature range, T
OPR
(typ/max)
-55…+80 / -40…+100; -269…+250**
Storage temperature, T
STR
+5…+40
Maximum deviation over temperature
0.75
Relative deviation of linear coefficient A
1
from its average value
±
5…± 20
Aging first year/next years max.
±
5 /
±
25
FS Pressure Hysteresis
< 0.02
Reproducibility of temperature dependence of crystal frequency
0.05
f
T
=f
O
+B
1
*T+B
2
*T
2
Vibration Resistance,
∆f/f
0
5g / 50-2000 Hz, 8 hours / ±7 ppm max.
*A
1
, A
2
and A
3
coefficients are specified on request.
**Temperature range can be increased from -269 to +250 °C on request.
Temperature sensing quartz crystal RKT206 is used for compensation of a temperature deviation of BRKM-P.
+0.50
23.00 0.00
PACKAGE DIMENSIONS
P2
UNITS: millimeters
1 – bottom diaphragm
2 - gasket
3 – upper diaphragm
4 – cover
5 – gauge internal cavity
6 – connecting pipe
7 – contact leads
6
+0.50
25.00 0.00
5
4
3
2
1
7
P1
GmbH & Co. KG
Wasemweg 5
D-74821 Mosbach
page
1(1)
www.AXTAL.com
fon: +49 (6261) 939834
fax: +49 (6261) 939836
Germany
E-mail: info@axtal.com
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