forked from zietzm/Helmholtz_Test_Bench
Martin Zietz
89 lines
2.9 KiB
Python
89 lines
2.9 KiB
Python
# import time
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from pyps2000b import PS2000B
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import globals as g
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def set_devices(): # creates device objects for all PSUs
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g.xyDevice = PS2000B.PS2000B(g.xyPort)
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g.zDevice = PS2000B.PS2000B(g.zPort)
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g.xAxis = (g.xyDevice, 0, g.relayPins[0], 0) # (device, channel, arduino pin, axis index)
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g.yAxis = (g.xyDevice, 1, g.relayPins[1], 1)
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g.zAxis = (g.zDevice, 0, g.relayPins[2], 2)
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def activate_all(): # enables remote control and output on all PSUs and channels
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g.xyDevice.enable_all()
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g.zDevice.enable_all()
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def deactivate_all(): # disables remote control and output on all PSUs and channels
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g.xyDevice.disable_all()
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g.zDevice.disable_all()
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def safe_arduino(): # sets output pins to low and closes serial connection
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for pin in g.relayPins:
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g.arduino.digitalWrite(pin, "LOW")
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g.arduino.close()
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def print_status(axis): # axis as (device, channel), e.g. g.xAxis
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device = axis[0] # PSU
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channel = axis[1] # output channel on the PSU
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print("%s, %0.2f V, %0.2f A"
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% (device.get_device_status_information(channel), device.get_voltage(channel), device.get_current(channel)))
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def print_status_3():
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print("X-Axis:")
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print_status(g.xAxis)
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print("Y-Axis:")
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print_status(g.yAxis)
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print("Z-Axis:")
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print_status(g.zAxis)
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def set_to_zero(device):
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device.voltage1 = 0
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device.current1 = 0
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device.current2 = 0
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device.current2 = 0
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def set_field_simple(vector): # forms magnetic field as specified by vector, w/o cancelling ambient field
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i_vec = vector/g.Coil_const
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set_current_vec(i_vec)
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def set_field(vector): # forms magnetic field as specified by vector, corrected for ambient field
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field = vector - g.ambientField
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i_vec = field/g.Coil_const
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set_current_vec(i_vec)
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def set_current_vec(i_vec): # sets needed currents on each axis for given vector
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set_axis_current(g.xAxis, i_vec[0])
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set_axis_current(g.yAxis, i_vec[1])
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set_axis_current(g.zAxis, i_vec[2])
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def set_axis_current(axis, value): # sets current with correct polarity on one axis
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device = axis[0]
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channel = axis[1]
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ardPin = axis[2]
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axisIndex = axis[3]
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if abs(value) > g.maxAmps[axisIndex]: # prevent excessive currents
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set_to_zero(device) # set currents and voltages to 0
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device.disable_all() # disable outputs on PSU
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safe_arduino() # set arduino pins to low and close serial link
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raise ValueError("Invalid current value. Tried %0.2fA, max. %0.2fA allowed" % (value, g.maxAmps[axisIndex]))
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elif value >= 0: # switch polarity as needed
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g.arduino.digitalWrite(ardPin, "LOW")
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elif value < 0:
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g.arduino.digitalWrite(ardPin, "HIGH")
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else:
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raise Exception("This should be impossible.")
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device.set_current(abs(value), channel)
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device.set_voltage(1.1 * g.maxAmps[axisIndex] * g.resistances[axisIndex]) # set max voltage high enough
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