draft of B field rotation

1 files changed, 71 insertions, 16 deletions

diff --git a/examples/eit_with_vcsel.py b/examples/eit_with_vcsel.py
index 913c4b7..daa021b 100644
--- a/examples/eit_with_vcsel.py
+++ b/examples/eit_with_vcsel.py
@@ -76,17 +76,51 @@ ai['coil_driver'] = ps
 
 
 logger.info('Setting magnetic field coils currents')
-"""
-Rough magnetic field calibration of the 3 axes coils
-- Ch1: 70mA -> 650 kHz shift for delta m = 2
-- Ch2: 70mA -> 700 kHz shift for delta m = 2
-- Ch2: 70mA -> 659 kHz shift for delta m = 2
-"""
-ps.setChanIout_mA(1, 70)
-ps.setChanIout_mA(2, 0)
-ps.setChanIout_mA(3, 0)
+# ps.setChanIout_mA(1, 70)
+# ps.setChanIout_mA(2, 0)
+# ps.setChanIout_mA(3, 0)
 logger.info('Done setting magnetic field coils currents')
 
+def setB(B=50e-6, theta=0, phi=0):
+    """ Sets B field currents based on B (in T) and angles theta, and phi """
+
+    """
+    Rough magnetic field calibration of the 3 axes coils in large magnetic shield
+    - Ch1: 70mA -> 650 kHz shift for delta m = 2
+    - Ch2: 70mA -> 700 kHz shift for delta m = 2
+    - Ch2: 70mA -> 659 kHz shift for delta m = 2
+    A better calibration obtained on 20220601 see file 
+      20220601.magnetic_field_callibration/calibration_currentToB.dat
+    """
+    # B response to current in a given channel
+    Bslope_TperA = {
+            1: 0.0006574710928926532,
+            2: 0.0007064314754023079,
+            3: 0.0006635058865577695
+            }
+
+    Bx = B*np.sin(theta)*np.cos(phi)
+    By = B*np.sin(theta)*np.sin(phi)
+    Bz = B*np.cos(theta)
+
+    # assuming that Ch1 controls Bz, Ch2 -> By, Ch3 -> Bx
+    chX=3; chY=2; chZ=1
+
+    Ix = Bx / Bslope_TperA[chX]
+    Iy = By / Bslope_TperA[chY]
+    Iz = Bz / Bslope_TperA[chZ]
+
+    logger.info(f"Setting {chX=} to {Ix}")
+    logger.info(f"Setting {chY=} to {Iy}")
+    logger.info(f"Setting {chZ=} to {Iz}")
+    # ps.setChanIout(chX, Ix)
+    # ps.setChanIout(chY, Iy)
+    # ps.setChanIout(chZ, Iz)
+    return Ix, Iy, Iz
+
+def setBdegrees(B=50e-6, theta=0, phi=0):
+    return setB(B=B, theta=theta/180*np.pi, phi=phi/180*np.pi)
+
 def eitSweep(central_frequency, frequency_span, Np, Nsweeps=1):
     frList = np.linspace(central_frequency-frequency_span/2, central_frequency+frequency_span/2, Np)
     trFreq=Trace('Frequency')
@@ -118,7 +152,7 @@ def eitSweep(central_frequency, frequency_span, Np, Nsweeps=1):
 
     return trEIT
 
-def eitVsCurrent(ch=1):
+def getCurrentCalibrationData(ch=1):
     curList = [20, 30, 40, 50, 60, 70, 80, 90, 100, 110]
     ps.setChanIout_mA(1, 0)
     ps.setChanIout_mA(2, 0)
@@ -133,16 +167,37 @@ def eitVsCurrent(ch=1):
         logger.info(f'Data saved to {fn=}')
         trEIT.save(fn)
 
+def calibrateCoilsCurrent():
+    Np=1000
+    Nsweeps=5
+    getCurrentCalibrationData(ch=1)
+    getCurrentCalibrationData(ch=2)
+    getCurrentCalibrationData(ch=3)
+
+def rotateBandGetEITtrace():
+    Np=100
+    Nsweeps=1
+    B=50e-6 # earth magnetic field in Tesla (0.5 G)
+    phiStep = 5
+    thetaStep = 5
+    phiSet = range(0,90+phiStep, phiStep)
+    thetaSet = range(0,90+thetaStep, thetaStep)
+    for phi in phiSet:
+        for theta in thetaSet:
+            setBdegrees(B=B, theta=theta, phi=phi)
+            trEIT = eitSweep(central_frequency, frequency_span, Np, Nsweeps=Nsweeps)
+            fn = apparatus.getNextDataFile()
+            logger.info(f'Data ready for {B=} in {theta=} {phi=}')
+            logger.info(f'Data saved to {fn=}')
+            trEIT.save(fn)
+
+
 central_frequency = 6.83468e9
 frequency_span =  2500e3
 
 dwellTime=0.1
-Np=1000
-Nsweeps=5
-
+Np=100
+Nsweeps=1
 
-eitVsCurrent(ch=1)
-eitVsCurrent(ch=2)
-eitVsCurrent(ch=3)
 
 tsdb_ingester.commit()