Appendix 9 Frequently Asked Questions -Faq - Aanderaa 4330 Operating Manual

Appendix 9 Frequently Asked Questions –FAQ
In this chapter we present a copy of our FAQ for the Optodes. The latest version is on our web site, refer
IMPORTANT! This FAQ is general for all versions of AADI Oxygen Optodes; all features described in the FAQ are not are not available for all Optode
versions.
Calibration, Calibration Coefficients, Accuracy and Precision
CCAP1
Q: What calibration coefficients are used in the sensor, how can I make sure that I use the correct ones?
A: The sensor has several sets of calibration constants stored in its memory.
These can be verified from your PC via the AADI Real-Time Collector software or with a terminal communication program like Hyperterminal or Tera
Terminal.
The coefficients are:
1. The internal temperature sensor has its own calibration constants that do not need to be changed by the user.
2. The sensing foil has a set of 28 constants C
(normally produced in batches of 100). If you change the foil with a foil from a different batch you must update the foil constants stored in the sensor
with a set of new constants by entering them manually into the sensor.
These constants are delivered on a calibration certificate together with the new foil. For multipoint calibrated Optodes the SVU(Stern Volmer
Uchida) formula is used for describing the relationship between phase shift/temperature and oxygen concentration. (Enable SVUformula set to
'yes'). The coefficients in this formula are stored in the SVUFoilCoef property
3. In order to adjust for sensor to sensor variation linear correction of the O
ConcCoef and ConcCoef
0
sensor. When changing or removing the foil a new calibration must be performed to obtain accuracy.
The most efficient way to do this calibration is to use the OxyView software or for 4330, 4831 and 4835 a terminal program like HyperTerminal or
Tera Terminal (ref. Manual of these sensors for detailed instructions)
4. When data from the sensor is registered on an Aanderaa data-logger (e.g. on a RCM 9, a buoy etc.) the old Aanderaa specific SR10 format is used.
These readings then need to be post-processed (converted to the desired engineering units) by multiplying with a constant.
This constant is obtained by dividing the range by the 10-bit resolution of the SR10 format.
to C (FoilCoefA
0 4
respectively. When performing a two point calibration these coefficients will be updated automatically and stored in the
1
,FoilCoefB for Optode 4330 and 4835), which are specific to that batch of foils
0-13 0-13
.
0..6
concentration is used. This offset and slope coefficients are stored in
2
page 66 of 93
TD 269 OPERATING MANUAL
OXYGEN OPTODE 4330, 4831, 4835
June 2017
www.aanderaa.com