User`s manual

Section 5: Configure Menu, Part III - Calibration Coefficients
57
Oxygen Calibration Coefficients
Enter the coefficients, which vary depending on the type of oxygen sensor,
from the calibration sheet:
• Beckman- or YSI-type sensor (manufactured by Sea-Bird or other
manufacturer) - These sensors require two channels - one for oxygen
current (enter m, b, soc, boc, tcor, pcor, tau, and wt) and the other for
oxygen temperature (enter k and c). Make sure to select both when
configuring the instrument.
Note: SEASAVE can process data for an instrument interfacing with up to
two Beckman- or YSI-type oxygen sensors when using the New Style or
Old Style configuration.
• IOW sensor - These sensors require two channels - one for oxygen
current (enter b0 and b1) and the other for oxygen temperature (enter a0,
a1, a2, and a3). Make sure to select both when configuring the instrument.
Value = b0 + [b1 * (a0 +a1 * T + a2 * T
2
+ a3 * T
3
) * C]
where
T is oxygen temperature voltage, C is oxygen current voltage
• Sea-Bird sensor (SBE 43) (New style configuration only) -
This sensor requires only one channel. Enter Soc, Boc, Voffset, tcor, pcor,
and tau.
OX
=
[Soc*{(V+Voffset)+(tau*δV/δt)}+Boc*exp(-0.03T)]*exp(tcor*T+pcor*P)*Oxsat(T,S)
where
OX = dissolved oxygen concentration (ml/l)
T = measured temperature from CTD (ºC)
P = measured pressure from CTD (decibars)
S = calculated salinity from CTD (PSU)
V = temperature-compensated oxygen signal (volts)
δV/δt = derivative of oxygen signal (volts/sec)
Oxsat(T,S) = oxygen saturation (ml/l)
Note: SEASAVE can process data for an instrument interfacing with up to
two SBE 43 oxygen sensors when using the New Style configuration.
PAR/Irradiance Calibration Coefficients
Underwater PAR Sensor
Enter M, B, calibration constant, multiplier, and offset.
PAR = [multiplier * (10
9
* 10
(V-B) / M
) / calibration constant] + offset
Where
Calibration constant, M, and B are dependent on sensor type.
• Biospherical PAR sensor
- PAR sensor with built-in log amplifier (QSP-200L, QSP-2300L,
QCP-2300L, or MCP-2300)]:
Typically, M = 1.0 and B = 0.0.
Calibration constant
= 10
5
/ wet calibration factor from Biospherical calibration sheet.
- PAR sensor without built-in log amplifier (QSP-200PD, QSP-2200 (PD),
or QCP 2200 (PD)):
M and B are taken from Sea-Bird calibration sheet.
Calibration constant
= C
S
calibration coefficient from Sea-Bird calibration sheet
= 10
9
/ calibration coefficient from Biospherical calibration sheet
• LI-COR PAR sensor
Calibration constant is LI-COR in water calibration constant.
Enter calibration constant, M, and B from calibration sheet.
Notes:
• Enter soc and boc values from the
most recent field calibration for
Beckman-type, YSI-type, or Sea-
Bird (SBE 43) oxygen sensor.
• See Application Notes 13-1 and
13-3 for complete description of
calculation of calibration
coefficients for Beckman- or
YSI-type sensors.
• See Application Notes 64 and 64-2
for complete description of
calculation of SBE 43 calibration
coefficients.
• Oxygen values computed by
SEASAVE and SBE Data
Processing’s Data Conversion
module differ from values
computed by SBE Data
Processing’s Derive module. Both
algorithms use the derivative of the
oxygen signal with respect to time:
! Quick estimate -
SEASAVE and Data Conversion
compute the derivative looking
back in time, because they share
common code and SEASAVE
cannot use future values while
acquiring real-time data.
! Most accurate results -
Derive uses a user-input
centered window (equal number
of points before and after scan)
to compute the derivative.
Note:
See Application Notes 11 LICOR
(LI-COR sensor), 11 QSP-L
(Biospherical sensor with built-in
log amplifier), and 11-QSP-PD
(Biospherical sensor without
built-in log amplifier) for complete
description of calculation of
calibration coefficients.