forked from zietzm/Helmholtz_Test_Bench
Martin Zietz
94 lines
3.1 KiB
Python
94 lines
3.1 KiB
Python
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.XY_DEVICE = PS2000B.PS2000B(g.XY_PORT)
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g.Z_DEVICE = PS2000B.PS2000B(g.Z_PORT)
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g.X_AXIS = (g.XY_DEVICE, 0, g.RELAY_PINS[0], 0) # (device, channel, arduino pin, axis index)
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g.Y_AXIS = (g.XY_DEVICE, 1, g.RELAY_PINS[1], 1)
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g.Z_AXIS = (g.Z_DEVICE, 0, g.RELAY_PINS[2], 2)
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def activate_all(): # enables remote control and output on all PSUs and channels
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g.XY_DEVICE.enable_all()
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g.Z_DEVICE.enable_all()
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def deactivate_all(): # disables remote control and output on all PSUs and channels
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g.XY_DEVICE.disable_all()
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g.Z_DEVICE.disable_all()
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def setup_arduino():
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for pin in g.RELAY_PINS:
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g.ARDUINO.pinMode(pin, "Output")
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g.ARDUINO.digitalWrite(pin, "LOW")
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def safe_arduino(): # sets output pins to low and closes serial connection
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for pin in g.RELAY_PINS:
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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 control variable, stored in globals.py
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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.X_AXIS)
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print("Y-Axis:")
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print_status(g.Y_AXIS)
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print("Z-Axis:")
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print_status(g.Z_AXIS)
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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.AMBIENT_FIELD
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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.X_AXIS, i_vec[0])
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set_axis_current(g.Y_AXIS, i_vec[1])
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set_axis_current(g.Z_AXIS, 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.MAX_AMPS[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.MAX_AMPS[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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maxVoltage = min(max(1.1 * g.MAX_AMPS[axisIndex] * g.RESISTANCES[axisIndex], 12), g.MAX_VOLTS) # limit voltage
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device.set_voltage(maxVoltage)
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