241 lines
8.2 KiB
Python
241 lines
8.2 KiB
Python
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import serial
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import serial.tools.list_ports
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import threading
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import time
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from typing import Optional, Dict, Any
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class SerialManager:
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"""
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串口管理器 - 负责所有串口通信功能
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采用单例模式确保串口只被创建一次
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"""
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_instance = None
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_initialized = False
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def __new__(cls, *args, **kwargs):
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"""单例模式实现"""
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if cls._instance is None:
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cls._instance = super(SerialManager, cls).__new__(cls)
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return cls._instance
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def __init__(self, port: str = None, baudrate: int = 9600,
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timeout: float = 1.0, write_timeout: float = 1.0):
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"""
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初始化串口管理器
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Args:
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port: 串口端口，如 "COM1" 或 "/dev/ttyUSB0"
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baudrate: 波特率，默认9600
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timeout: 读超时时间（秒）
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write_timeout: 写超时时间（秒）
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"""
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if self._initialized:
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return
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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.write_timeout = write_timeout
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# 串口对象和连接状态
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self.serial_obj = None
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self.is_connected = False
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# 线程安全锁
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self.serial_lock = threading.Lock()
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# 初始化串口连接
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self._init_serial_connection()
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self._initialized = True
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def _init_serial_connection(self):
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"""初始化串口连接"""
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if not self.port:
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self._auto_detect_port()
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if not self.port:
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print("⚠ 未找到可用串口")
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return
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try:
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self.serial_obj = serial.Serial(
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port=self.port,
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baudrate=self.baudrate,
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bytesize=8,
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parity='N',
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stopbits=1,
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timeout=self.timeout,
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write_timeout=self.write_timeout
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)
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if self.serial_obj.is_open:
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self.is_connected = True
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print(f"✓ 串口连接成功: {self.port} ({self.baudrate}bps)")
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else:
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print(f"⚠ 串口打开失败: {self.port}")
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except Exception as e:
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print(f"⚠ 串口连接失败: {e}")
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self.is_connected = False
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def _auto_detect_port(self):
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"""自动检测可用串口"""
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try:
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available_ports = list(serial.tools.list_ports.comports())
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if available_ports:
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print(f"检测到可用串口: {[port.device for port in available_ports]}")
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import platform
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system = platform.system()
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if system == "Windows":
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# Windows系统优先选择COM3、COM4等
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for port in available_ports:
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if port.device in ["COM3", "COM4", "COM5", "COM6"]:
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self.port = port.device
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break
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else:
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self.port = available_ports[0].device
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else:
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# Linux系统优先选择USB串口
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for port in available_ports:
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if "USB" in port.description or "ttyUSB" in port.device:
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self.port = port.device
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break
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else:
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self.port = available_ports[0].device
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except Exception as e:
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print(f"串口检测失败: {e}")
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def _modbus_crc16(self, data: bytes) -> bytes:
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"""计算Modbus CRC16校验码"""
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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 >>= 1
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return bytes([crc & 0xFF, (crc >> 8) & 0xFF])
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def send_modbus_command(self, unit: int, function_code: int,
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data: bytes, expected_response_len: int = 8) -> Dict[str, Any]:
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"""
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发送Modbus命令
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Args:
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unit: 从站地址
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function_code: 功能码
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data: 数据字节
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expected_response_len: 期望响应长度
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Returns:
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包含操作结果的字典
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"""
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if not self.is_connected or not self.serial_obj:
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return {"success": False, "error": "串口未连接"}
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with self.serial_lock:
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try:
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# 构建请求帧
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request_frame = bytes([unit & 0xFF, function_code & 0xFF]) + data
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crc = self._modbus_crc16(request_frame)
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full_request = request_frame + crc
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# 清空缓冲区
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self.serial_obj.reset_input_buffer()
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# 发送请求
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self.serial_obj.write(full_request)
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self.serial_obj.flush()
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print(f"📤 发送Modbus命令: {full_request.hex(' ').upper()}")
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# 读取响应
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time.sleep(0.1) # 等待设备响应
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response = self.serial_obj.read(expected_response_len)
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if len(response) < expected_response_len:
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return {"success": False, "error": "响应超时或长度不足", "raw": response}
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# CRC校验
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if len(response) >= 4:
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response_data = response[:-2]
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response_crc = response[-2:]
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calculated_crc = self._modbus_crc16(response_data)
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if response_crc != calculated_crc:
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return {"success": False, "error": "CRC校验失败", "raw": response}
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return {
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"success": True,
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"raw": response,
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"raw_hex": response.hex(' ').upper()
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}
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except Exception as e:
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return {"success": False, "error": f"串口通信异常: {str(e)}"}
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def write_single_coil(self, unit: int, coil_addr: int, value: bool) -> bool:
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"""
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写单个线圈（功能码0x05）
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Args:
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unit: 从站地址
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coil_addr: 线圈地址
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value: 线圈值（True/False）
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Returns:
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操作是否成功
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"""
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data = bytes([
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(coil_addr >> 8) & 0xFF, # 地址高字节
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coil_addr & 0xFF, # 地址低字节
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0xFF if value else 0x00, # 值高字节
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0x00 # 值低字节
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])
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result = self.send_modbus_command(unit, 0x05, data, 8)
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return result["success"]
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def read_holding_registers(self, unit: int, start_addr: int, quantity: int) -> Dict[str, Any]:
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"""
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读取保持寄存器（功能码0x03）
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Args:
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unit: 从站地址
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start_addr: 起始地址
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quantity: 读取数量
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Returns:
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包含寄存器数据的字典
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"""
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data = bytes([
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(start_addr >> 8) & 0xFF, # 起始地址高字节
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start_addr & 0xFF, # 起始地址低字节
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(quantity >> 8) & 0xFF, # 数量高字节
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quantity & 0xFF # 数量低字节
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])
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return self.send_modbus_command(unit, 0x03, data, 5 + 2 * quantity)
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def close(self):
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"""关闭串口连接"""
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if self.serial_obj and self.is_connected:
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try:
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self.serial_obj.close()
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self.is_connected = False
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print("✓ 串口连接已关闭")
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except Exception as e:
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print(f"⚠ 关闭串口失败: {e}")
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def get_status(self) -> Dict[str, Any]:
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"""获取串口状态"""
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return {
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"is_connected": self.is_connected,
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"port": self.port,
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"baudrate": self.baudrate
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}
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