python - 模拟发现 2 与 Python API

import ctypes # import the C compatible data types from sys import platform, path # this is needed to check the OS type and get the PATH from os import sep # OS specific file path separators # load the dynamic library, get constants path (the path is OS specific) if platform.startswith("win"): # on Windows dwf = ctypes.cdll.dwf constants_path = "C:" + sep + "Program Files (x86)" + sep + "Digilent" + sep + "WaveFormsSDK" + sep + "samples" + sep + "py" elif platform.startswith("darwin"): # on macOS lib_path = sep + "Library" + sep + "Frameworks" + sep + "dwf.framework" + sep + "dwf" dwf = ctypes.cdll.LoadLibrary(lib_path) constants_path = sep + "Applications" + sep + "WaveForms.app" + sep + "Contents" + sep + "Resources" + sep + "SDK" + sep + "samples" + sep + "py" else: # on Linux dwf = ctypes.cdll.LoadLibrary("libdwf.so") constants_path = sep + "usr" + sep + "share" + sep + "digilent" + sep + "waveforms" + sep + "samples" + sep + "py" # import constants path.append(constants_path) import dwfconstants as constants class data: """ stores the device handle and the device name """ handle = ctypes.c_int(0) name = "" """ stores the sampling frequency and the buffer size """ sampling_frequency = 20e06 buffer_size = 8192 def open_AD2(): """ open the first available device """ # this is the device handle - it will be used by all functions to "address" the connected device device_handle = ctypes.c_int() # connect to the first available device dwf.FDwfDeviceOpen(ctypes.c_int(-1), ctypes.byref(device_handle)) data.handle = device_handle return data def open_oscilloscope(device_data, sampling_frequency=20e06, buffer_size=8192, offset=0, amplitude_range=5): """ initialize the oscilloscope parameters: - device data - sampling frequency in Hz, default is 20MHz - buffer size, default is 8192 - offset voltage in Volts, default is 0V - amplitude range in Volts, default is ±5V """ # enable all channels dwf.FDwfAnalogInChannelEnableSet(device_data.handle, ctypes.c_int(0), ctypes.c_bool(True)) # set offset voltage (in Volts) dwf.FDwfAnalogInChannelOffsetSet(device_data.handle, ctypes.c_int(0), ctypes.c_double(offset)) # set range (maximum signal amplitude in Volts) dwf.FDwfAnalogInChannelRangeSet(device_data.handle, ctypes.c_int(0), ctypes.c_double(amplitude_range)) # set the buffer size (data point in a recording) dwf.FDwfAnalogInBufferSizeSet(device_data.handle, ctypes.c_int(buffer_size)) # set the acquisition frequency (in Hz) dwf.FDwfAnalogInFrequencySet(device_data.handle, ctypes.c_double(sampling_frequency)) # disable averaging (for more info check the documentation) dwf.FDwfAnalogInChannelFilterSet(device_data.handle, ctypes.c_int(-1), constants.filterDecimate) data.sampling_frequency = sampling_frequency data.buffer_size = buffer_size return def measure_oscilloscope(device_data, channel): """ measure a voltage parameters: - device data - the selected oscilloscope channel (1-2, or 1-4) returns: - the measured voltage in Volts """ # set up the instrument dwf.FDwfAnalogInConfigure(device_data.handle, ctypes.c_bool(False), ctypes.c_bool(False)) # read data to an internal buffer dwf.FDwfAnalogInStatus(device_data.handle, ctypes.c_bool(False), ctypes.c_int(0)) # extract data from that buffer voltage = ctypes.c_double() # variable to store the measured voltage dwf.FDwfAnalogInStatusSample(device_data.handle, ctypes.c_int(channel - 1), ctypes.byref(voltage)) # store the result as float voltage = voltage.value return voltage def record_oscilloscope(device_data, channel): """ record an analog signal parameters: - device data - the selected oscilloscope channel (1-2, or 1-4) returns: - buffer - a list with the recorded voltages - time - a list with the time moments for each voltage in seconds (with the same index as "buffer") """ # set up the instrument dwf.FDwfAnalogInConfigure(device_data.handle, ctypes.c_bool(False), ctypes.c_bool(True)) # read data to an internal buffer while True: status = ctypes.c_byte() # variable to store buffer status dwf.FDwfAnalogInStatus(device_data.handle, ctypes.c_bool(True), ctypes.byref(status)) # check internal buffer status if status.value == constants.DwfStateDone.value: # exit loop when ready break # copy buffer buffer = (ctypes.c_double * data.buffer_size)() # create an empty buffer dwf.FDwfAnalogInStatusData(device_data.handle, ctypes.c_int(channel - 1), buffer, ctypes.c_int(data.buffer_size)) # calculate aquisition time time = range(0, data.buffer_size) time = [moment / data.sampling_frequency for moment in time] # convert into list buffer = [float(element) for element in buffer] return buffer, time def close_oscilloscope(device_data): """ reset the scope """ dwf.FDwfAnalogInReset(device_data.handle) return class function: """ function names """ custom = constants.funcCustom sine = constants.funcSine square = constants.funcSquare triangle = constants.funcTriangle noise = constants.funcNoise dc = constants.funcDC pulse = constants.funcPulse trapezium = constants.funcTrapezium sine_power = constants.funcSinePower ramp_up = constants.funcRampUp ramp_down = constants.funcRampDown def generate_function(device_data, channel, function, offset, frequency=1e03, amplitude=1, symmetry=50, wait=0, run_time=0, repeat=0, data=[]): """ generate an analog signal parameters: - device data - the selected wavegen channel (1-2) - function - possible: custom, sine, square, triangle, noise, ds, pulse, trapezium, sine_power, ramp_up, ramp_down - offset voltage in Volts - frequency in Hz, default is 1KHz - amplitude in Volts, default is 1V - signal symmetry in percentage, default is 50% - wait time in seconds, default is 0s - run time in seconds, default is infinite (0) - repeat count, default is infinite (0) - data - list of voltages, used only if function=custom, default is empty """ # enable channel channel = ctypes.c_int(channel - 1) dwf.FDwfAnalogOutNodeEnableSet(device_data.handle, channel, constants.AnalogOutNodeCarrier, ctypes.c_bool(True)) # set function type dwf.FDwfAnalogOutNodeFunctionSet(device_data.handle, channel, constants.AnalogOutNodeCarrier, function) # load data if the function type is custom if function == constants.funcCustom: data_length = len(data) buffer = (ctypes.c_double * data_length)() for index in range(0, len(buffer)): buffer[index] = ctypes.c_double(data[index]) dwf.FDwfAnalogOutNodeDataSet(device_data.handle, channel, constants.AnalogOutNodeCarrier, buffer, ctypes.c_int(data_length)) # set frequency dwf.FDwfAnalogOutNodeFrequencySet(device_data.handle, channel, constants.AnalogOutNodeCarrier, ctypes.c_double(frequency)) # set amplitude or DC voltage dwf.FDwfAnalogOutNodeAmplitudeSet(device_data.handle, channel, constants.AnalogOutNodeCarrier, ctypes.c_double(amplitude)) # set offset dwf.FDwfAnalogOutNodeOffsetSet(device_data.handle, channel, constants.AnalogOutNodeCarrier, ctypes.c_double(offset)) # set symmetry dwf.FDwfAnalogOutNodeSymmetrySet(device_data.handle, channel, constants.AnalogOutNodeCarrier, ctypes.c_double(symmetry)) # set running time limit dwf.FDwfAnalogOutRunSet(device_data.handle, channel, ctypes.c_double(run_time)) # set wait time before start dwf.FDwfAnalogOutWaitSet(device_data.handle, channel, ctypes.c_double(wait)) # set number of repeating cycles dwf.FDwfAnalogOutRepeatSet(device_data.handle, channel, ctypes.c_int(repeat)) # start dwf.FDwfAnalogOutConfigure(device_data.handle, channel, ctypes.c_bool(True)) return def close_function(device_data, channel=0): """ reset a wavegen channel, or all channels (channel=0) """ channel = ctypes.c_int(channel - 1) dwf.FDwfAnalogOutReset(device_data.handle, channel) return def _switch_fixed(device_data, master_state, positive_state, negative_state): """ turn the power supplies on/off parameters: - device data - master switch - True = on, False = off - positive supply switch - True = on, False = off - negative supply switch - True = on, False = off """ # enable/disable the positive supply dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(0), ctypes.c_int(0), ctypes.c_int(positive_state)) # enable the negative supply dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(1), ctypes.c_int(0), ctypes.c_int(negative_state)) # start/stop the supplies - master switch dwf.FDwfAnalogIOEnableSet(device_data.handle, ctypes.c_int(master_state)) return def _switch_variable_(device_data, master_state, positive_state, negative_state, positive_voltage, negative_voltage): """ turn the power supplies on/off parameters: - device data - master switch - True = on, False = off - positive supply switch - True = on, False = off - negative supply switch - True = on, False = off - positive supply voltage in Volts - negative supply voltage in Volts """ # set positive voltage positive_voltage = max(0, min(5, positive_voltage)) dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(0), ctypes.c_int(1), ctypes.c_double(positive_voltage)) # set negative voltage negative_voltage = max(-5, min(0, negative_voltage)) dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(1), ctypes.c_int(1), ctypes.c_double(negative_voltage)) # enable/disable the positive supply dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(0), ctypes.c_int(0), ctypes.c_int(positive_state)) # enable the negative supply dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(1), ctypes.c_int(0), ctypes.c_int(negative_state)) # start/stop the supplies - master switch dwf.FDwfAnalogIOEnableSet(device_data.handle, ctypes.c_int(master_state)) return def open_multimeter(device_data): """ initialize the digital multimeter """ # enable the DMM dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(3), ctypes.c_int(0), ctypes.c_double(1.0)) return def measure_multimeter(device_data, mode, ac=False, range=0, high_impedance=False): """ measure a voltage/current/resistance/continuity/temperature parameters: - device data - mode: "voltage", "low current", "high current", "resistance", "continuity", "diode", "temperature" - ac: True means AC value, False means DC value, default is DC - range: voltage/current/resistance/temperature range, 0 means auto, default is auto - high_impedance: input impedance for DC voltage measurement, False means 10MΩ, True means 10GΩ, default is 10MΩ returns: - the measured value in V/A/Ω/°C, or None on error """ # set voltage mode if mode == "voltage": # set coupling if ac: dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(3), ctypes.c_int(1), constants.DwfDmmACVoltage) else: dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(3), ctypes.c_int(1), constants.DwfDmmDCVoltage) # set input impedance if high_impedance: dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(3), ctypes.c_int(5), ctypes.c_double(1)) else: dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(3), ctypes.c_int(5), ctypes.c_double(0)) # set high current mode elif mode == "high current": # set coupling if ac: dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(3), ctypes.c_int(1), constants.DwfDmmACCurrent) else: dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(3), ctypes.c_int(1), constants.DwfDmmDCCurrent) # set low current mode elif mode == "low current": # set coupling if ac: dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(3), ctypes.c_int(1), constants.DwfDmmACLowCurrent) else: dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(3), ctypes.c_int(1), constants.DwfDmmDCLowCurrent) # set resistance mode elif mode == "resistance": dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(3), ctypes.c_int(1), constants.DwfDmmResistance) # set continuity mode elif mode == "continuity": dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(3), ctypes.c_int(1), constants.DwfDmmContinuity) # set diode mode elif mode == "diode": dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(3), ctypes.c_int(1), constants.DwfDmmDiode) # set temperature mode elif mode == "temperature": dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(3), ctypes.c_int(1), constants.DwfDmmTemperature) # set range dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(3), ctypes.c_int(2), ctypes.c_double(range)) # fetch analog I/O status if dwf.FDwfAnalogIOStatus(device_data.handle) == 0: # signal error return None # get reading measurement = ctypes.c_double() dwf.FDwfAnalogIOChannelNodeStatus(device_data.handle, ctypes.c_int(3), ctypes.c_int(3), ctypes.byref(measurement)) return measurement.value def close_multimeter(device_data): """ reset the instrument """ # disable the DMM dwf.FDwfAnalogIOChannelNodeSet(device_data.handle, ctypes.c_int(3), ctypes.c_int(0), ctypes.c_double(0)) # reset the instrument dwf.FDwfAnalogIOReset(device_data.handle) return def close(device_data): """ close a specific device """ dwf.FDwfDeviceClose(device_data.handle) return def main(): print("Starting") device = open_AD2() _switch_variable_(device, True, True, False, 3, 3) open_oscilloscope(device) measurement = measure_oscilloscope(device, 1) print(measurement) measurement = measure_oscilloscope(device, 2) print(measurement) close_oscilloscope(device) open_multimeter(device) measurement = measure_multimeter(device, "voltage") print(measurement) close_multimeter(device) print("Finishing" ) #close(device) if __name__ == "__main__": main()