Appendix C - Highly Precise Pressure Transducer - idronaut Ocean Seven 304Plus Operator's Manual

APPENDIX C – HIGHLY PRECISE PRESSURE TRANSDUCER
C.1 INTRODUCTION
The OCEAN SEVEN 304Plus CTD CTD can interface the Highly Precise Pressure Transducer through
a dedicated hardware and software interface. The below section contains all the information needed to
operate an OS304Plus CTD which interfaces the Highly Precise Pressure Transducer.
C.2 HIGHLY PRECISE PRESSURE TRANSDUCER
This high-precision 0,01 %FS pressure transmitter is based on the stable, floating piezoresisitive
transducer and the newly developed XEMICS microprocessor with an integrated 16-bit A/D converter.
Temperature dependency and non-linearity of the sensor are mathematically compensated by the
interfacing electronics. The output rate is 400 Hz.
C.2.1 Accuracy and Precision
"Accuracy" is an absolute term, "Precision" a relative term. Deadweight testers are primary standards
for pressure, where the pressure is defined by the primary values of mass, length and time. Higher
class primary standards in national laboratories indicate the uncertainty of their pressure references
with 70 to 90 ppM or close to 0.01%. Commercial deadweight testers used to calibrate the transmitters
indicate an uncertainty or accuracy of 0.025 %. Below these levels, expression "Precision" is the ability
of a pressure transmitter to be at each pressure point within 0.01 %FS relative to these commercial
standards.
C.2.2 Technical specifications
Available ranges:
Overpressure:
Output :
Supply (V):
Accuracy, Error Band (-10...80 °C):
Precision (10...40 °C):
Output Rate:
Resolution:
Long-term stability typycal.:
Load Resistance (ohm):
Electrical Connection:
Insulation :
Storage/Operating T. range:
Pressure Endurance:
Vibration Endurance:
Shock Endurance:
Protection:
CE-Conformity:
Material in Contact with Media :
Weight:
Dead Volume Change:
Connector:
C.2.3 Polynomial Compensation
This uses a mathematical model to derive the precise pressure value (P) from the signals measured by
the pressure sensor (S) and the temperature sensor (T). The microprocessor in the transmitter
calculates P using the following polynomial:
IDRONAUT – Brugherio (MB)
Standard Pressure Ranges (FS) and Overpressure in Bar
0,8...1,2 3
2 5
RS 485
8...28 Vcc
0,1 % FS
0,01 %FS ranges ³ 10 bar
400 Hz
0,002 %FS
Gauges:1 mbar or 0,05 %FS
Absolute: 0,5 mbar or 0,025 %FS (10...40 °C)
<(U-7V) / 0,02A (2-wire) > 5'000 (3-wire)
- MIL C-26482-Plug (6 pole)
- Binder-Plug 723 (5 pole)
- DIN 43650 Plug (4 pole)
100 Mohm / 50 V
-40...120 °C
10 Million Pressure Cycles 0...100 %FS at 25 °C
20 g (5...2000 Hz, max. amplitude ± 3 mm),
according to IEC 68 2-6
20 g (11 ms)
IP65 optional: IP 67 or IP68 (with cable)
EN 50081-2, EN 50082-2
HASTELLOY
30 g;
< 0,1 mm3
Molex Milli-Grid 2 mm.
OCEAN SEVEN 304Plus CTD
10 30 100
20 60 200
61
300 1000
400 1000
12-2015