idronaut Ocean Seven 304Plus Operator's Manual page 62

APPENDIX A – DISSOLVED OXYGEN SENSOR
A.5 CONFIGURATION
Through the CTD set-up, it is possible to configure the oxygen sensor too. The first parameter to
configure allows the operator to define the time-out spent by the CTD before starting the
measurement. The warm-up time-out is used by the CTD to wait for the dissolved oxygen sensor
stabilization. The stabilization is mandatory as the dissolved oxygen sensor must be properly
polarized before it can perform reliable and accurate measurements.
Warm-up time-out
The warm-up time-out in seconds must be configured as 30s.
Configuration of the dissolved oxygen sensor in the list of acquired sensors:
OCEAN SEVEN 304Plus
Id
01
02
03
04
05
06
CMD:I)nitialize,M)odify,D)elete,Q)uit
At the end of the list, commands available to perform the configuration are shown below:
Initialize: completely deletes the list.
Modify:
Delete:
Quit:
The following parameters can be configured by means of the "Modify" command:
Sensor code[0..24,255=NU] 6
Sensor mux.[0..3,255=NU] 1
Sensor precision [0..6] 1
A.6 CALIBRATION
The oxygen sensor is the sensor which requires most attention of all the OCEAN SEVEN sensors.
Maintenance (mostly membrane and electrolyte replacement) should be carried out at least every
three months and assembling/disassembling requires great care. Calibration of the sensor should be
carried out:
 after a long period of disuse;
 once a day during an extended field survey.
It is preferable to calibrate the oxygen sensor in a liquid (ideally distilled water) saturated (i.e. in
perfect equilibrium) with ambient air and well stirred to have homogeneous temperature. If possible,
check the oxygen saturation using the Winkler method. However, this procedure is seldom used
because of the difficulties of obtaining a solution homogeneous in temperature and at saturation,
particularly in the field. For this reason, the calibration is usually carried out in air.
A.6.1 Oxygen sensor calibration in air
After the"Oxygen Sensor" has been selected, typing its index code at the sensor selection prompt, the
CTD displays:
IDRONAUT – Brugherio (MB)
Name Code Mux Digits
Press 0000 253
Temp 0001 253
Cond 0002 254
Sal 0004 255 0003
O2% 0006 001
O2pmm 0005 255
allows the operator to enter a new sensor/parameter in the list or modify an existing
one. See below for the details about configuration.
allows the operator to delete a configured sensor/parameter from the list.
terminates the data acquisition parameter editing and ends the configuration
command too. The new configuration is stored in a non-volatile memory.
0002
0003
0003
0001
0002
OCEAN SEVEN 304Plus CTD
54
12-2015