idronaut Ocean Seven 304Plus Operator's Manual page 70

APPENDIX C – HIGHLY PRECISE PRESSURE TRANSDUCER
P(S,T) = A(T).S 0 + B(T).S 1 + C(T).S 2 + D(T).S 3
With the following coefficients A(T)...D(T) depending on the temperature:
A(T) = A 0 . T 0 + A 1 . T 1 + A 2 . T 2 + A 3 . T 3
B(T) = B 0 . T 0 + B 1 . T 1 + B 2 . T 2 + B 3 . T 3
C(T) = C 0 . T 0 + C 1 . T 1 + C 2 . T 2 + C 3 . T 3
D(T) = D 0 . T 0 + D 1 . T 1 + D 2 . T 2 + D 3 . T 3
The transmitter is factory-tested at various levels of pressure and temperature. The corresponding
measured values of S, together with the exact pressure and temperature values, allow the coefficients
A0...D3 to be calculated. These are written into the EEPROM of the microprocessor. When the
pressure transmitter is in service, the microprocessor measures the signals (S) and (T), calculates the
coefficients according to the temperature and produces the exact pressure value by solving the P(S,T)
equation. Calculations and conversions are performed at least 400 times per second.
C.3 CONFIGURATION
Through the CTD set-up, it is possible to configure the Highly Precise Sensor by adding or modifying
an existing sensor and associating the logical code 0 to this sensor and associating the multiplexer
input 252 special code.
C.4 SENSOR CALIBRATION
Calibration is carried out as described in the Operator's Manual for the standard pressure sensor.
However, the following calibration coefficients must be configured:
Coefficient (a) = 0.0
Coefficient (b) = 10.0
Coefficient (c) = 0.0
IDRONAUT – Brugherio (MB) OCEAN SEVEN 304Plus CTD
62
12-2015