Aanderaa 4330 Operating Manual page 82

new switch ON?
A: Yes, the sensor will always do a sample after power up. The data output is after approximately 2 seconds. Approximately 2 seconds power off is needed
to assure a new reset of the Optode. So in total it is recommended to supply power to the sensor for a minimum of 5 seconds during each sampling period.
SSC 10
Q: If I have internally set the sensors sample interval to 2 seconds and then decide to mount it on e.g. an RCM9 current meter, logging at a 1 hour sample
interval, will there be a conflict between the sensor's internal interval and the one used by the RCM9?
A: No, there will not be any conflict. When the Optode is used with an Aanderaa data logger the power is only applied when the data-logger scans the
connected sensors (Control Voltage is active). Every time the sensor is powered up, regardless of the internal interval settings, it will output one data
reading (requires that the SR10 output is enabled, see Operating Manual for more information). The same happens for the AiCap/RS-232 output. Even if the
sensor is set up for long measurement intervals it will output new data every time power is connected. If power is connected continuously the sensor will
measure at the programmed time interval (anything from 1 second and upwards).
SSC 11
Q: I have connected the Optode to my Aanderaa current meter but no data is delivered from the sensor, why?
A: The Optode output has to be set to -1 or -2 to present data on the SR10 output channel. Please refer to the Operating Manual or the OxyView software
for more information on how this is done.
SSC 12
Q: What should I think about if I want to use the Optode mounted on a water column profiling CTD or a towed vehicle?
A: In spite of the relatively slow response time with respect to these applications many customers have chosen to use the sensor mounted on a CTD, a
profiling vehicle or a towed vehicle. Users have selected the Optode mainly because of the long-term stability and the absence of pressure hysteresis.
Mainly pressure hysteresis makes electrochemical sensors unreliable when profiling at depths beyond 500-1000 meters. Weather the slow response time of
the Optode will be an impediment to getting good data or not depends of course on how strong the gradients are and at what speed you are profiling/towing.
Data from some successful profiling applications are presented in several peer reviewed scientific papers. For more information please look at the Aanderaa
Internet pages.
SSC 13
Q: How should I connect and mount the sensor on for example a CTD or a towed vehicle?
A: If the CTD is equipped with a fast responding temperature sensor it is better to do the temperature compensation externally. This will improve the
accuracy when subjected to fast temperature changes (when going through a gradient). The Optode must then be configured to output the phase shift
information (Phase). Based on this data and the temperature data from the CTD, the oxygen concentration can be calculated with formulas (see the
Operating Manual for details). If the CTD is not able to receive the RS-232 output, the Oxygen Optode 3975 or 4831 with analog output can be used. The
two channel "intelligent" digital to analog converter supplied with this sensor is able to output two channels of your selection (including Phase). The Optode
has normally been mounted on the lower part of the CTD and with the window (where the foil is) close to a horizontal frame tube of the CTD. The
page 82 of 93
TD 269 OPERATING MANUAL
OXYGEN OPTODE 4330, 4831, 4835
June 2017