259 lines
8.3 KiB
Python
259 lines
8.3 KiB
Python
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import serial
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import time
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import struct
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class InovanceMD520:
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def __init__(self, port='COM4', baudrate=9600, timeout=1):
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"""
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初始化汇川MD520变频器通信
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:param port: 串口名称，Windows为COMx，Linux为/dev/ttyUSBx
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:param baudrate: 波特率，默认9600
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:param timeout: 超时时间，秒
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"""
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self.port = port
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self.baudrate = baudrate
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self.timeout = timeout
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self.ser = None
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def connect(self):
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"""连接串口"""
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try:
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self.ser = serial.Serial(
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port=self.port,
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baudrate=self.baudrate,
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bytesize=serial.EIGHTBITS,
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parity=serial.PARITY_NONE,
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stopbits=serial.STOPBITS_ONE,
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timeout=self.timeout
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)
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print(f"成功连接到串口 {self.port}")
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return True
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except serial.SerialException as e:
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print(f"连接串口失败: {e}")
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return False
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def disconnect(self):
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"""断开串口连接"""
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if self.ser and self.ser.is_open:
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self.ser.close()
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print("串口连接已关闭")
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def calculate_crc(self, data):
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"""
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计算Modbus CRC16校验码
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:param data: 字节数据
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:return: CRC校验码（低位在前，高位在后）
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"""
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crc = 0xFFFF
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for byte in data:
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crc ^= byte
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for _ in range(8):
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if crc & 0x0001:
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crc = (crc >> 1) ^ 0xA001
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else:
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crc = crc >> 1
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return struct.pack('<H', crc) # 小端序，低位在前
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def query_frequency(self, slave_addr=0x01):
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"""
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查询变频器运行频率
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:param slave_addr: 从站地址，默认1
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:return: 频率值（Hz），如查询失败返回None
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"""
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if not self.ser or not self.ser.is_open:
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print("串口未连接")
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return None
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# 构建查询指令：读取运行频率（地址1001H）
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# 01 03 10 01 00 01
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cmd_data = bytes([
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slave_addr, # 从站地址
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0x03, # 功能码：读取保持寄存器
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0x10, 0x01, # 寄存器地址：1001H（运行频率）
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0x00, 0x01 # 读取1个寄存器
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])
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# 计算CRC
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crc = self.calculate_crc(cmd_data)
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# 完整指令
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full_cmd = cmd_data + crc
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print(f"发送查询指令: {full_cmd.hex().upper()}")
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try:
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# 清空输入缓冲区
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self.ser.reset_input_buffer()
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# 发送指令
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self.ser.write(full_cmd)
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# 等待响应（根据文档需要等待3.5个字节时间）
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time.sleep(0.01) # 约10ms延迟
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# 读取响应
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# 正常响应格式：地址(1) + 功能码(1) + 字节数(1) + 数据(2) + CRC(2) = 7字节
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response = self.ser.read(7)
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if len(response) < 7:
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print(f"响应数据长度不足: {len(response)} 字节")
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return None
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print(f"收到响应: {response.hex().upper()}")
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# 验证响应
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if response[0] != slave_addr:
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print(f"从站地址不匹配: 期望{slave_addr:02X}, 收到{response[0]:02X}")
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return None
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if response[1] != 0x03:
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print(f"功能码错误: 期望03, 收到{response[1]:02X}")
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return None
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if response[2] != 0x02:
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print(f"数据长度错误: 期望02, 收到{response[2]:02X}")
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return None
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# 验证CRC
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received_crc = response[-2:]
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calculated_crc = self.calculate_crc(response[:-2])
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if received_crc != calculated_crc:
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print("CRC校验失败")
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return None
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# 解析频率数据（高字节在前）
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frequency_raw = (response[3] << 8) | response[4]
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frequency_hz = frequency_raw / 100.0 # 转换为Hz（单位0.01Hz）
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print(f"原始频率值: {frequency_raw} (0x{frequency_raw:04X})")
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print(f"实际频率: {frequency_hz:.2f} Hz")
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return frequency_hz
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except Exception as e:
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print(f"通信错误: {e}")
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return None
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def read_register(self, slave_addr, register_addr, register_count=1):
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"""
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通用读取寄存器方法
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:param slave_addr: 从站地址
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:param register_addr: 寄存器地址（16位）
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:param register_count: 读取的寄存器数量
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:return: 读取的数据列表
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"""
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if not self.ser or not self.ser.is_open:
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print("串口未连接")
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return None
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# 构建读取指令
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cmd_data = bytes([
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slave_addr, # 从站地址
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0x03, # 功能码：读取保持寄存器
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(register_addr >> 8) & 0xFF, # 寄存器地址高字节
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register_addr & 0xFF, # 寄存器地址低字节
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(register_count >> 8) & 0xFF, # 寄存器数量高字节
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register_count & 0xFF # 寄存器数量低字节
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])
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# 计算CRC
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crc = self.calculate_crc(cmd_data)
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full_cmd = cmd_data + crc
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print(f"发送读取指令: {full_cmd.hex().upper()}")
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try:
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self.ser.reset_input_buffer()
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self.ser.write(full_cmd)
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time.sleep(0.01)
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# 计算预期响应长度
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expected_length = 5 + 2 * register_count # 地址1 + 功能码1 + 字节数1 + 数据2*N + CRC2
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response = self.ser.read(expected_length)
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if len(response) < expected_length:
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print(f"响应数据长度不足: {len(response)} 字节，期望 {expected_length} 字节")
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return None
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print(f"收到响应: {response.hex().upper()}")
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# 验证CRC
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received_crc = response[-2:]
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calculated_crc = self.calculate_crc(response[:-2])
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if received_crc != calculated_crc:
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print("CRC校验失败")
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return None
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# 解析数据
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data_length = response[2]
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data_bytes = response[3:3 + data_length]
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results = []
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for i in range(0, len(data_bytes), 2):
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value = (data_bytes[i] << 8) | data_bytes[i + 1]
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results.append(value)
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return results
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except Exception as e:
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print(f"通信错误: {e}")
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return None
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def main():
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# 创建变频器对象
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inverter = InovanceMD520(port='COM4', baudrate=9600)
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# 连接串口
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if not inverter.connect():
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return
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try:
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while True:
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print("\n" + "=" * 50)
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print("汇川MD520变频器频率查询")
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print("=" * 50)
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# 查询运行频率
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frequency = inverter.query_frequency(slave_addr=0x01)
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if frequency is not None:
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print(f"✅ 当前运行频率: {frequency:.2f} Hz")
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else:
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print("❌ 频率查询失败")
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# 可选：读取其他监控参数
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print("\n--- 其他监控参数 ---")
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# 读取母线电压 (地址1002H)
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voltage_data = inverter.read_register(0x01, 0x1002)
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if voltage_data:
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voltage = voltage_data[0] / 10.0 # 单位0.1V
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print(f"母线电压: {voltage:.1f} V")
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# 读取输出电压 (地址1003H)
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output_voltage_data = inverter.read_register(0x01, 0x1003)
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if output_voltage_data:
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output_voltage = output_voltage_data[0] # 单位1V
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print(f"输出电压: {output_voltage} V")
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# 读取输出电流 (地址1004H)
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current_data = inverter.read_register(0x01, 0x1004)
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if current_data:
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current = current_data[0] / 100.0 # 单位0.01A
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print(f"输出电流: {current:.2f} A")
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# 等待5秒后再次查询
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print("\n等待5秒后继续查询...")
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time.sleep(5)
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except KeyboardInterrupt:
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print("\n用户中断查询")
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finally:
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# 断开连接
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inverter.disconnect()
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if __name__ == "__main__":
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main()
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