AD5933测量阻抗代码

以下是AD5933测量阻抗的示例代码，供参考：

import smbus
import time
import math
 
# AD5933 Registers
ADDR = 0x0D
REG_CTRL_HB = 0x80
REG_CTRL_LB = 0x81
REG_FREQ_START = 0x82
REG_FREQ_INC = 0x85
REG_NUM_INC = 0x88
REG_NUM_SETTLE = 0x8A
REG_STATUS = 0x8F
REG_REAL_DATA = 0x94
REG_IMAG_DATA = 0x96
 
# AD5933 Control Register High Byte Bits
CTRL_HB_INIT_START_FREQ = 0x10
CTRL_HB_START_SWEEP = 0x20
CTRL_HB_INC_FREQ = 0x30
CTRL_HB_REPEAT_FREQ = 0x40
CTRL_HB_MEASURE_TEMP = 0x80
 
# AD5933 Control Register Low Byte Bits
CTRL_LB_RANGE_2000 = 0x00
CTRL_LB_RANGE_200 = 0x01
CTRL_LB_RANGE_20 = 0x02
CTRL_LB_RANGE_2 = 0x03
CTRL_LB_PGA_GAIN_1 = 0x00
CTRL_LB_PGA_GAIN_5 = 0x04
CTRL_LB_PGA_GAIN_10 = 0x08
CTRL_LB_PGA_GAIN_50 = 0x0C
CTRL_LB_PGA_GAIN_100 = 0x10
CTRL_LB_PGA_GAIN_200 = 0x14
CTRL_LB_PGA_GAIN_400 = 0x18
CTRL_LB_PGA_GAIN_1000 = 0x1C
CTRL_LB_SYNC_OUT = 0x20
CTRL_LB_SYNC_IN_TEMP = 0x40
 
class AD5933:
 
    def __init__(self, bus, address=ADDR):
        self.bus = smbus.SMBus(bus)
        self.address = address
        self.gain = 1
        self.range = 2000
 
    def reset(self):
        self.bus.write_byte_data(self.address, REG_CTRL_HB, 0x10)
 
    def set_range(self, range):
        self.range = range
        self.bus.write_byte_data(self.address, REG_CTRL_LB, self.range)
 
    def set_gain(self, gain):
        self.gain = gain
        self.bus.write_byte_data(self.address, REG_CTRL_LB, self.gain)
 
    def set_frequency(self, freq):
        freq_word = int(freq * 2**27 / 16000000)
        self.bus.write_byte_data(self.address, REG_FREQ_START, (freq_word & 0xFF0000) >> 16)
        self.bus.write_byte_data(self.address, REG_FREQ_START + 1, (freq_word & 0x00FF00) >> 8)
        self.bus.write_byte_data(self.address, REG_FREQ_START + 2, (freq_word & 0x0000FF))
 
    def set_increment(self, inc):
        inc_word = int(inc * 2**27 / 16000000)
        self.bus.write_byte_data(self.address, REG_FREQ_INC, (inc_word & 0xFF0000) >> 16)
        self.bus.write_byte_data(self.address, REG_FREQ_INC + 1, (inc_word & 0x00FF00) >> 8)
        self.bus.write_byte_data(self.address, REG_FREQ_INC + 2, (inc_word & 0x0000FF))
 
    def set_num_increments(self, num):
        self.bus.write_byte_data(self.address, REG_NUM_INC, (num & 0xFF00) >> 8)
        self.bus.write_byte_data(self.address, REG_NUM_INC + 1, (num & 0x00FF))
 
    def set_num_settling_cycles(self, num):
        self.bus.write_byte_data(self.address, REG_NUM_SETTLE, num)
 
    def start_sweep(self):
        ctrl_hb = CTRL_HB_INIT_START_FREQ | CTRL_HB_START_SWEEP | CTRL_HB_INC_FREQ
        self.bus.write_byte_data(self.address, REG_CTRL_HB, ctrl_hb)
 
    def get_status(self):
        return self.bus.read_byte_data(self.address, REG_STATUS)
 
    def wait_for_status(self, mask):
        while True:
            status = self.get_status()
            if (status & mask) == mask:
                break
            time.sleep(0.1)
 
    def get_real(self):
        real_data = self.bus.read_byte_data(self.address, REG_REAL_DATA)
        real_data |= self.bus.read_byte_data(self.address, REG_REAL_DATA + 1) << 8
        if (real_data & 0x8000) > 0:
            real_data -= 65536
        return real_data
 
    def get_imaginary(self):
        imag_data = self.bus.read_byte_data(self.address, REG_IMAG_DATA)
        imag_data |= self.bus.read_byte_data(self.address, REG_IMAG_DATA + 1) << 8
        if (imag_data & 0x8000) > 0:
            imag_data -= 65536
        return imag_data
 
    def get_magnitude(self):
        real = self.get_real()
        imag = self.get_imaginary()
        return math.sqrt(real**2 + imag**2) / 2**15 * self.range / self.gain
 
    def get_phase(self):
        real = self.get_real()
        imag = self.get_imaginary()
        phase = math.atan2(imag, real) * 180 / math.pi
        if phase < 0:
            phase += 360
        return phase
 
    def measure_impedance(self, freq, gain=1, range=2000, num_increments=10, num_settling_cycles=10):
        self.set_gain(gain)
        self.set_range(range)
        self.set_frequency(freq)
        self.set_increment(freq / num_increments)
        self.set_num_increments(num_increments)
        self.set_num_settling_cycles(num_settling_cycles)
        self.start_sweep()
        self.wait_for_status(0x02)
        return self.get_magnitude(), self.get_phase()

使用方法：

# 初始化AD5933
ad5933 = AD5933(1)

# 复位
ad5933.reset()

# 测量阻抗
freq = 1000  # 频率
gain = 1  # 增益
range = 2000  # 量程
num_increments = 10  # 段数
num_settling_cycles = 10  # 平稳周期
magnitude, phase = ad5933.measure_impedance(freq, gain, range, num_increments, num_settling_cycles)