class EmissionControl(threading.Thread):
""" Control the emission of a filament. """
def __init__(self, datasocket=None):
threading.Thread.__init__(self)
if datasocket is not None:
self.datasocket = datasocket
else:
self.datasocket = None
self.measured_voltage = 0
self.filament = {}
port = '/dev/serial/by-id/usb-TTI_CPX400_Series_PSU_C2F952E5-if00'
self.filament['device'] = CPX.CPX400DPDriver(1, device=port)
self.filament['voltage'] = 0
self.filament['current'] = 0
self.filament['idle_voltage'] = 3
self.filament['device'].set_current_limit(4)
self.filament['device'].output_status(True)
self.bias = {}
self.bias['device'] = CPX.CPX400DPDriver(2, device=port)
self.bias['grid_voltage'] = 0
self.bias['grid_current'] = 0
self.bias['device'].output_status(True)
self.looptime = 0
self.update_setpoint(0.1)
i2c_helper = ABEHelpers()
bus = i2c_helper.get_smbus()
self.adc = DeltaSigma(bus, 0x68, 0x69, 18)
self.adc.set_pga(1) # This shold be 8, but amplifier seems broken on the available device
self.running = True
self.wanted_voltage = 0
self.emission_current = 999
self.pid = pid.PID(2, 0.03, 0, 9)
self.pid.update_setpoint(self.setpoint)
def set_bias(self, bias):
""" Set the bias-voltage """
if self.datasocket is not None:
self.datasocket.set_point_now('ionenergy', bias)
if bias > -1:
self.bias['device'].set_voltage(bias)
if bias < 5:
pass # TODO: Implement check to make sure not to melt the filament
def update_setpoint(self, setpoint):
""" Update the setpoint """
self.setpoint = setpoint
if self.datasocket is not None:
self.datasocket.set_point_now('setpoint', setpoint)
def set_filament_voltage(self, U):
""" Set the filament voltage """
return(self.filament['device'].set_voltage(U))
def read_filament_voltage(self):
""" Read the filament voltage """
return(self.filament['device'].read_actual_voltage())
def read_filament_current(self):
""" Read the filament current """
return(self.filament['device'].read_actual_current())
def read_grid_voltage(self):
"""Read the actual grid voltage """
return(self.bias['device'].read_actual_voltage())
def read_grid_current(self):
""" Read the grid current as measured by power supply """
return(self.bias['device'].read_actual_current())
def read_emission_current(self):
""" Read the actual emission current """
value = self.adc.read_voltage(5)
self.measured_voltage = value
current = 1000.0 * value / 3.4 # Resistance value read off component label
return(current)
def run(self):
while self.running:
#time.sleep(0.1)
t = time.time()
self.emission_current = self.read_emission_current()
self.wanted_voltage = self.pid.wanted_power(self.emission_current) + self.filament['idle_voltage']
self.pid.update_setpoint(self.setpoint)
self.set_filament_voltage(self.wanted_voltage)
self.filament['voltage'] = self.read_filament_voltage()
self.filament['current'] = self.read_filament_current()
self.bias['grid_voltage'] = self.read_grid_voltage()
self.bias['grid_current'] = self.read_grid_current()
if self.datasocket is not None:
self.datasocket.set_point_now('emission', self.emission_current)
self.looptime = time.time() - t
self.setpoint = 0
self.set_filament_voltage(0)
self.set_bias(0)
