Appendix 3 Electronic Design - Aanderaa 4330 Operating Manual

Appendix 3 Electronic Design

Figure A 6 Functional diagram
Figure A 6 illustrates the main functions of the electronics.
To obtain good oxygen measurements the electronic circuit must be able to measure the phase between
the excitation signal and the received signal accurately and with good resolution.
The received signal is sampled with a frequency of four times the excitation frequency. Two signal
components with a phase difference of 90 degrees are extracted from these samples and are used for
calculations of the phase of the received signal.
The O -concentration is calculated after linearizing and temperature compensating the phase
2
measurements.
A thermistor thermally connected to the sensor body, provides temperature measurements.
Appendix 4 Mechanical Design of Optode 4330 and 4831
Figure 1-1 and Figure 1-2 and Figure 1-3 and A8 for illustration of the Oxygen Optode 4330.
A cylindrical titanium housing shields the electronics from the surrounding water and high pressure
(pressure resistance for standard sensor is 6000 m. These sensors do also exist in a special 12 000 m
rated version).
A 4mm thick sapphire window provides the optical connection between the optics inside the Optode and
the sensing foil on the outside.
The foil is fixed to the window by a POM securing plate and is easily replaceable.
For the 4330 a 10-pin receptacle in the sensor foot provides all electrical connection to the sensor.
To prevent potential leakage from the sensor to the rest of the measurement system, the receptacle is
moulded inside a receptacle housing.
For the 4831 the receptacle is an 8 pin Subconn
Note! The sensor should not be opened! Opening the sensor housing can breach the warranty (ref.
CHAPTER 6 , page 37 for instructions on how to change the Sensing Foil).
TD 269 OPERATING MANUAL
OXYGEN OPTODE 4330, 4831, 4835
June 2017
MCBH8M wet-mate connector.
Electronics
Securing plate
page 50 of 93