Example 15: deri_bprpres and deri_bprtemp, BPR channels

Loggers with BPR channels interface a Paroscientific, Inc. transducer. The logger measures 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 (peri00 and peri01). 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 types 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 Paroscientific, 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 Paroscientific, 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.

Examples

>> calibration 3 type
<< calibration 3 type = bpr_08
>> calibration 4 type
<< calibration 4 type = bpr_09

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
>> 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

Set the pressure coefficients provided by Paroscientific, Inc.

>> calibration 4 datetime = 20171123120722, x0 = 5.8310298E+00, x1 = -3.8981210E+03, x2 = -10.493120E+03, x3 = 0.0000000E+00
<< calibration 4 datetime = 20171123120722, x0 = 5.8310300e+000, x1 = -3.8981210e+003, x2 = -10.493120e+003, x3 = 0.0000000e+000

Set the temperature coefficients provided by Paroscientific, Inc.

>> calibration 3
<< 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
<< 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

Request confirmation of all pressure and temperature calibration coefficients.