RSP Calibration

RSP calibration files are ASCII files with metadata and calibration data.

The units of RSP calibration files are interpreted to be:

  • Frequency in Hz

  • Magnitude in mV/nT

  • Phase in degrees

Resistics will automatically convert these units to:

  • Frequency in Hz

  • Magnitude in mV/nT (including any static gain)

  • Phase in radians

Note

Remember that extension happens in the original units of the calibration data. For RSP data files, this is in mV/nT.

Naming in the project environment

When using the project environment, resistics automatically searches for calibration files in the calData folder. RSP files should be named according to the following specification:

Important

[*]TYPE-[SENSORNUM]_[BOARD]-ID-[SERIAL].RSP

or

[*]TYPE-[SENSORNUM]_BB-ID-[SERIAL].RSP

where:

  • SENSORNUM is the sensor number out of the sensor type written with three digits (i.e. leading zeros required if the sensor number is less than three digits)

  • BOARD is either LF (chopper on) or HF (chopper off)

  • SERIAL is the serial number written with six digits (i.e. leading zeros required if the serial number is less than six digits)

  • [*] represents any general string.

The BB files represent broadband calibration files that cover both chopper on and chopper off cases.

As an example, consider an induction coil with,

  • sensor type MFS06

  • sensor serial number 307

  • Chopper off

then,

  • SENSORNUM = 006

  • BOARD = HF

  • SERIAL = 000307

Therefore, the file could be named:

  • Metronix_Coil—–TYPE-006_HF-ID-000307.RSP

  • Metronix_Coil—–TYPE-006_BB-ID-000307.RSP

Example

The class CalibrationIO can be used to read in RSP calibration files.

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from datapaths import calPath, calImages
from resistics.calibrate.io import CalibrationIO

# read RSP calibration data - this is a broadband calibraition - no chopper on or off
filepath = calPath / "Metronix_Coil-----TYPE-006_BB-ID-000307.RSP"
calIO = CalibrationIO(filepath, "rsp", extend=False)
calData = calIO.read()
calData.printInfo()

When using CalibrationIO to read a calibration file, the filepath and calibration data format (rsp) need to be defined. Further, the extension rule can be optionally passed. Because RSP files only contain one set of calibration data (unlike Metronix files which may have calibration data for both chopper on and off), the chopper keyword is unused for reading RSP files.

The method read() returns a CalibrationData object. Information about this can be printed to the terminal, giving:

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14:10:49 CalibrationData: ####################
14:10:49 CalibrationData: CALIBRATIONDATA INFO BEGIN
14:10:49 CalibrationData: ####################
14:10:49 CalibrationData: Filename = calData\Metronix_Coil-----TYPE-006_BB-ID-000307.RSP
14:10:49 CalibrationData: Serial = 307
14:10:49 CalibrationData: Sensor = 006_HF
14:10:49 CalibrationData: Static gain = 800.00
14:10:49 CalibrationData: Chopper = False
14:10:49 CalibrationData: Number of frequency points = 40
14:10:49 CalibrationData: Calibration data:
14:10:49 CalibrationData:          Frequency [Hz]       Mag. [mv/nT]    Phase [rad]
14:10:49 CalibrationData:              0.00001000             0.00            1.57
14:10:49 CalibrationData:              0.00010000             0.02            1.57
14:10:49 CalibrationData:              0.00100000             0.20            1.57
14:10:49 CalibrationData:              0.01000000             2.00            1.57
14:10:49 CalibrationData:              0.02000000             4.00            1.57
14:10:49 CalibrationData:              0.03000000             6.00            1.56
14:10:49 CalibrationData:              0.04000000             8.00            1.56
14:10:49 CalibrationData:              0.05000000            10.00            1.56
14:10:49 CalibrationData:              0.07000000            14.00            1.55
14:10:49 CalibrationData:              0.10000000            19.97            1.55
14:10:49 CalibrationData:              0.14678000            29.30            1.53
14:10:49 CalibrationData:              0.21544000            42.93            1.52
14:10:49 CalibrationData:              0.31623000            62.90            1.49
14:10:49 CalibrationData:              0.46416000            91.95            1.46
14:10:49 CalibrationData:              0.68130000           134.18            1.41
14:10:49 CalibrationData:              1.00000000           194.04            1.34
14:10:49 CalibrationData:              1.46780000           275.51            1.23
14:10:49 CalibrationData:              2.15440000           381.11            1.09
14:10:49 CalibrationData:              3.16230000           500.78            0.92
14:10:49 CalibrationData:              4.64160000           616.36            0.73
14:10:49 CalibrationData:              6.81300000           706.64            0.55
14:10:49 CalibrationData:             10.00000000           764.00            0.39
14:10:49 CalibrationData:             14.67800000           796.69            0.27
14:10:49 CalibrationData:             21.54500000           812.31            0.19
14:10:49 CalibrationData:             31.62300000           820.62            0.13
14:10:49 CalibrationData:             46.41600000           824.53            0.08
14:10:49 CalibrationData:             68.13000000           822.19            0.05
14:10:49 CalibrationData:            100.00000000           826.09            0.03
14:10:49 CalibrationData:            146.78000000           827.91            0.01
14:10:49 CalibrationData:            215.45000000           827.59           -0.01
14:10:49 CalibrationData:            316.23000000           827.04           -0.03
14:10:49 CalibrationData:            464.16000000           827.32           -0.05
14:10:49 CalibrationData:            681.30000000           828.12           -0.08
14:10:49 CalibrationData:           1000.00000000           829.22           -0.12
14:10:49 CalibrationData:           1467.80000000           828.29           -0.19
14:10:49 CalibrationData:           2154.50000000           816.08           -0.28
14:10:49 CalibrationData:           3162.30000000           797.63           -0.42
14:10:49 CalibrationData:           4641.70000000           720.48           -0.63
14:10:49 CalibrationData:           6813.00000000           619.91           -0.74
14:10:49 CalibrationData:          10000.00000000           571.23           -0.97
14:10:49 CalibrationData: ####################
14:10:49 CalibrationData: CALIBRATIONDATA INFO END
14:10:49 CalibrationData: ####################

Once the calibration data file is read in, the calibration curve can be viewed by using the view() method of CalibrationData. By passing a matplotlib figure to this, the layout of the plot can be controlled.

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# plot
import matplotlib.pyplot as plt

fig = plt.figure(figsize=(8, 8))
calData.view(fig=fig, label="RSP calibration", legend=True)
fig.tight_layout(rect=[0, 0.02, 1, 0.96])
plt.show()
fig.savefig(calImages / "calibrationRSP.png")
alternate text

Viewing the unextended calibration data

The calibration static gain is applied to the magnitude data by default. To view the data without static gain, pass staticgain=False to the view() call. Further, to plot the phase in degrees, pass degrees=True to view().

To visualise the influence of the static gain correction, the calibration data can be plotted with and without static gain as shown in the following example.

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# plot
import matplotlib.pyplot as plt

fig = plt.figure(figsize=(8, 8))
calData.view(fig=fig, label="RSP calibration", degrees=True, legend=True)
calData.view(
    fig=fig, staticgain=False, degrees=True, label="RSP no static gain", legend=True
)
fig.tight_layout(rect=[0, 0.02, 1, 0.96])
plt.show()
fig.savefig(calImages / "calibrationRSP_staticGainAndDegrees.png")
alternate text

Viewing the unextended calibration data with and without static gain

The calibration data can be written out in the internal ASCII format using the writeInternalFormat() method of CalibrationIO.

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# write as the ASCII format
rsp2ascii = calPath / "rsp2ascii.TXT"
calIO.writeInternalFormat(calData, rsp2ascii)

The internal ascii calibration format writes out values in the following units:

  • Magnitude in mV/nT

  • Phase in radians

This gives the file below:

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Serial = 307
Sensor = 006_HF
Static gain = 800.0
Magnitude unit = mV/nT
Phase unit = radians
Chopper = False

CALIBRATION DATA
+1.0000e-05  +2.5000e-06  +1.5708e+00
+1.0000e-04  +2.5000e-05  +1.5708e+00
+1.0000e-03  +2.5000e-04  +1.5705e+00
+1.0000e-02  +2.5000e-03  +1.5683e+00
+2.0000e-02  +4.9999e-03  +1.5658e+00
+3.0000e-02  +7.4998e-03  +1.5633e+00
+4.0000e-02  +9.9995e-03  +1.5608e+00
+5.0000e-02  +1.2499e-02  +1.5583e+00
+7.0000e-02  +1.7497e-02  +1.5533e+00
+1.0000e-01  +2.4959e-02  +1.5452e+00
+1.4678e-01  +3.6629e-02  +1.5339e+00
+2.1544e-01  +5.3666e-02  +1.5173e+00
+3.1623e-01  +7.8627e-02  +1.4931e+00
+4.6416e-01  +1.1493e-01  +1.4576e+00
+6.8130e-01  +1.6773e-01  +1.4051e+00
+1.0000e+00  +2.4255e-01  +1.3394e+00
+1.4678e+00  +3.4438e-01  +1.2296e+00
+2.1544e+00  +4.7639e-01  +1.0904e+00
+3.1623e+00  +6.2598e-01  +9.1815e-01
+4.6416e+00  +7.7045e-01  +7.2902e-01
+6.8130e+00  +8.8331e-01  +5.4810e-01
+1.0000e+01  +9.5500e-01  +3.9286e-01
+1.4678e+01  +9.9587e-01  +2.7489e-01
+2.1545e+01  +1.0154e+00  +1.8837e-01
+3.1623e+01  +1.0258e+00  +1.2735e-01
+4.6416e+01  +1.0307e+00  +8.4177e-02
+6.8130e+01  +1.0277e+00  +4.5146e-02
+1.0000e+02  +1.0326e+00  +2.8629e-02
+1.4678e+02  +1.0349e+00  +7.9399e-03
+2.1545e+02  +1.0345e+00  -7.9172e-03
+3.1623e+02  +1.0338e+00  -2.6454e-02
+4.6416e+02  +1.0341e+00  -4.8852e-02
+6.8130e+02  +1.0352e+00  -7.9795e-02
+1.0000e+03  +1.0365e+00  -1.2133e-01
+1.4678e+03  +1.0354e+00  -1.8783e-01
+2.1545e+03  +1.0201e+00  -2.8487e-01
+3.1623e+03  +9.9703e-01  -4.2295e-01
+4.6417e+03  +9.0061e-01  -6.2766e-01
+6.8130e+03  +7.7489e-01  -7.4444e-01
+1.0000e+04  +7.1404e-01  -9.7162e-01

Note

When writing out in internal format, the static gain is removed from the magnitude but recorded in the file. When reading in the internal format again, the static gain will be reapplied.

To read in the internal ASCII format calibration file, the parameters of CalibrationIO need to be reset using the refresh() method. This time, the fileformat needs to be set to “induction”.

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# can read this again
calIO.refresh(rsp2ascii, "induction", extend=False)
calDataAscii = calIO.read()
calDataAscii.printInfo()

Finally, plotting the original data and the internal ASCII format data can be done in the following way:

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# plot together
fig = plt.figure(figsize=(8, 8))
calData.view(fig=fig, label="RSP calibration", legend=True)
calDataAscii.view(fig=fig, label="ASCII calibration", legend=True)
fig.tight_layout(rect=[0, 0.02, 1, 0.96])
plt.show()
fig.savefig(calImages / "calibrationRSPvsASCII.png")

The resultant figure is:

alternate text

Viewing the original RSP data versus the ASCII data

Complete example script

For the purposes of clarity, the example script in full.

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from datapaths import calPath, calImages
from resistics.calibrate.io import CalibrationIO

# read RSP calibration data - this is a broadband calibraition - no chopper on or off
filepath = calPath / "Metronix_Coil-----TYPE-006_BB-ID-000307.RSP"
calIO = CalibrationIO(filepath, "rsp", extend=False)
calData = calIO.read()
calData.printInfo()

# plot
import matplotlib.pyplot as plt

fig = plt.figure(figsize=(8, 8))
calData.view(fig=fig, label="RSP calibration", legend=True)
fig.tight_layout(rect=[0, 0.02, 1, 0.96])
plt.show()
fig.savefig(calImages / "calibrationRSP.png")

# plot
import matplotlib.pyplot as plt

fig = plt.figure(figsize=(8, 8))
calData.view(fig=fig, label="RSP calibration", degrees=True, legend=True)
calData.view(
    fig=fig, staticgain=False, degrees=True, label="RSP no static gain", legend=True
)
fig.tight_layout(rect=[0, 0.02, 1, 0.96])
plt.show()
fig.savefig(calImages / "calibrationRSP_staticGainAndDegrees.png")

# write as the ASCII format
rsp2ascii = calPath / "rsp2ascii.TXT"
calIO.writeInternalFormat(calData, rsp2ascii)

# can read this again
calIO.refresh(rsp2ascii, "induction", extend=False)
calDataAscii = calIO.read()
calDataAscii.printInfo()

# plot together
fig = plt.figure(figsize=(8, 8))
calData.view(fig=fig, label="RSP calibration", legend=True)
calDataAscii.view(fig=fig, label="ASCII calibration", legend=True)
fig.tight_layout(rect=[0, 0.02, 1, 0.96])
plt.show()
fig.savefig(calImages / "calibrationRSPvsASCII.png")

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 Info MFS06 induction coil no.: 365 - date of calibration: Nov 2012
 Info BB - files HF and LF put together
 Info theoretical values used for f less than 0.1Hz
 StaticGain       800.00000000
 CalFile 
 Manufacturer Metronix_Coil-----                                          
 SensorType 006_HF
    FREQUENCY(Hz) AMPLITUDE(mV/nT)       PHASE(deg)
 --------------------------------------------------
  10000.00000000       0.68111250     -55.00600000
   7943.00000000       0.71691532     -47.00600000
   6309.40000000       0.75118139     -42.80600000
   5011.80000000       0.84298476     -39.21300000
   3981.00000000       0.92956350     -32.18700000
   3162.20000000       0.97526201     -25.51500000
   2511.80000000       1.00296174     -20.14600000
   1995.20000000       1.01615536     -15.37100000
   1584.90000000       1.02166616     -12.19400000
   1258.90000000       1.02757713      -9.60450000
   1000.00000000       1.02927500      -7.41570000
    794.30000000       1.03139855      -5.99240000
    630.95000000       1.03286515      -4.61200000
    501.18000000       1.03280668      -3.47730000
    398.10000000       1.03441309      -2.62020000
    316.22000000       1.03419751      -1.80970000
    251.19000000       1.03452602      -1.18630000
    199.52000000       1.03448626      -0.43138000
    158.49000000       1.03713875       0.00156320
    125.89000000       1.03530362       0.84879000
    100.00000000       1.03295000       1.56090000
     79.43000000       1.03249071       2.38410000
     63.09500000       1.03680859       3.30920000
     50.11800000       1.02867195       4.44710000
     39.81000000       1.02590370       5.50290000
     31.62200000       1.02609437       7.09880000
     25.11900000       1.01870105       9.11900000
     19.95200000       1.01256400      11.53900000
     15.84900000       1.00064643      14.52300000
     12.58900000       0.98378314      18.15600000
     10.00000000       0.95576250      22.41100000
      7.94300000       0.91780372      27.48100000
      6.30950000       0.86550566      33.02300000
      5.01180000       0.79844239      39.38100000
      3.98100000       0.71901836      46.10100000
      3.16230000       0.62751891      52.42100000
      2.51190000       0.53698142      58.62300000
      1.99520000       0.44989266      64.07800000
      1.58490000       0.37068830      68.95500000
      1.25890000       0.30175833      72.91200000
      1.00000000       0.24387500      76.25400000
      0.79430000       0.19548716      78.95400000
      0.63095000       0.15654658      81.02300000
      0.50119000       0.12492161      82.91800000
      0.39811000       0.09926375      84.36700000
      0.31623000       0.07913260      85.55200000
      0.25119000       0.06284774      86.40200000
      0.19953000       0.04990994      87.11700000
      0.15849000       0.03965618      87.66700000
      0.12589000       0.03152600      88.16100000
      0.10000000       0.02505375      88.52000000
      0.07000000       0.01749732      88.99693298
      0.05000000       0.01249902      89.28348541
      0.04000000       0.00999950      89.42677307
      0.03000000       0.00749979      89.57008362
      0.02000000       0.00499994      89.71337891
      0.01000000       0.00249999      89.85668945
      0.00100000       0.00025000      89.98566437
      0.00010000       0.00002500      89.99856567
      0.00001000       0.00000250      89.99985504