Loggers with BPR channels interface a Paroscientific, Inc. transducer. The logger measure precisely the output frequencies from the transducer. Those transducers generally outputs two signals, one for pressure and one for temperature.
There are two channels for the periods measured (peri_00 and peri_01). But in order to convert them in a meaningful pressure and temperature, the logger provides two channels which implement the calibration equation from Paroscientific, Inc. They rely on two type of equations: deri_bprpres (pressure in dbar) and deri_bprtemp (temperature in °C).
deri_bprpres equation
\begin{equation*} \begin{aligned} \text{Pressure (dbar)} & = (C \cdot (1 - (\dfrac{T_0}{T})^2)) \cdot (1 - D(1 - (\dfrac{T_0}{T})^2)) \cdot 0.689475728 \\ T & = value(n_0) \cdot 1e-6 \\ X & = value(n_1) \cdot 1e-6 \\ U & = X - x_0 \\ C & = x_1 + x_2 \cdot U + x_3 \times U^2 \\ D & = x_4 + x_5 \cdot U \\ T_0 & = x_6 + x_7 \cdot U + x_8 \cdot U^2 + x_9 \cdot U^3 + x_{10} \cdot U^4 \end{aligned} \end{equation*}- The coefficients x0 ... x10 are provided by Paroscientic, Inc. and are mapped according to the following bijection:
| Paroscientific Inc. coefficient | U0 | C1 | C2 | C3 | D1 | D2 | T1 | T2 | T3 | T4 | T5 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| deri_bprpres coefficient | x0 | x1 | x2 | x3 | x4 | x5 | x6 | x7 | x8 | x9 | x10 |
- n0 is the index of the pressure period channel, in this example 1
- value(n0) is the final output value of the pressure period channel in picoseconds.
- n1 is the index of the temperature period channel, in this example 2
- value(n1) is the final output value of the temperature period channel in picoseconds.
deri_bprtemp equation
\begin{equation*} \begin{aligned} \text{Temperature} & = x_1 \cdot U + x_2 \cdot U^2 + x_3 \cdot U^3 \\ X & = value(n_0) \cdot 1e-6 \\ U & = X - x_0 \end{aligned} \end{equation*}- The coefficients x0 ... x3 are provided by Paroscientic, Inc. and are mapped according to the following bijection:
| Paroscientific Inc. coefficient | U0 | Y1 | Y2 | Y3 |
|---|---|---|---|---|
| deri_bprtemp coefficient | x0 | x1 | x2 | x3 |
- n0 is the index of the temperature period channel, in this example 2
- value(n0) is the final output value of the temperature period channel in picoseconds.
>> calibration 3 type >> calibration 4 type Confirm the channel type. >> calibration 3 datetime= 20171123120721, x0 = 5.8310298E+00, x1 = -24.514029E+03, x2 = -573.64117E+00, x3 = 76.129281E+03, x4 = 35.688001E-03, x5 = 0.0000000E+00, x6 = 30.413169E+00, x7 = 664.14898E-03 << calibration 3 datetime = 20171123120721, x0 = 5.8310300e+000, x1 = -24.514030e+003, x2 = -573.64115e+000, x3 = 76.129280e+003, x4 = 35.688000e-003, x5 = 0.0000000e+000, x6 = 30.413170e+000, x7 = 664.14899e-003 Set the pressure coefficients provided by Paroscientific, Inc. Set the temperature coefficients provided by Paroscientific, Inc. >> calibration 3 >> calibration 4 Request confirmation of all pressure and temperature calibration coefficients.Examples
<< calibration 3 type = bpr_08
<< calibration 4 type = bpr_09
>> calibration 3 datetime = 20171123120721, x8 = 58.803409E+00, x9 = 180.91160E+00, x10 = 0.0000000E+00
<< calibration 3 datetime = 20171123120721, x8 = 58.803408e+000, x9 = 180.91160e+000, x10 = 0.0000000e+000
<< calibration 4 datetime = 20171123120722, x0 = 5.8310300e+000, x1 = -3.8981210e+003, x2 = -10.493120e+003, x3 = 0.0000000e+000
<< calibration 3 type = bpr_08, datetime = 20171123120721, x0 = 5.8310300e+000, x1 = -24.514030e+003, x2 = -573.64115e+000, x3 = 76.129280e+003, x4 = 35.688000e-003, x5 = 0.0000000e+000, x6 = 30.413170e+000, x7 = 664.14899e-003, x8 = 58.803408e+000, x9 = 180.91160e+000, x10 = 0.0000000e+000, n0 = 1, n1 = 2
<< calibration 4 type = bpr_09, datetime = 20171123120722, x0 = 5.8310300e+000, x1 = -3.8981210e+003, x2 = -10.493120e+003, x3 = 0.0000000e+000, n0 = 2