258 lines
8.8 KiB
Python
258 lines
8.8 KiB
Python
import snap7
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import logging
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from threading import Lock
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import time
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from snap7.util import *
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import ast
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class Snap7Client:
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"""Snap7客户端，处理与PLC的通信"""
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def __init__(self, ip, rack, slot, max_retries=5, retry_base_delay=1):
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"""
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初始化Snap7客户端
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Args:
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ip: PLC IP地址
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rack: Rack编号
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slot: Slot编号
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max_retries: 最大重试次数
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retry_base_delay: 基础重试延迟（秒）
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"""
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self.ip = ip
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self.rack = rack
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self.slot = slot
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self.client = snap7.client.Client()
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self.lock = Lock()
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self.connected = False
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self.max_retries = max_retries
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self.retry_base_delay = retry_base_delay
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self.last_connect_attempt = 0
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self.retry_count = 0
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self.logger = logging.getLogger(f"Snap7Client[{ip}]")
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def is_valid_connection(self):
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"""检查连接是否真正有效"""
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try:
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# 尝试读取PLC的运行状态
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cpu_state = self.client.get_cpu_state()
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print("当前 CPU 状态:", cpu_state)
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return cpu_state in ['S7CpuStatusRun', 'S7CpuStatusStop']
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except:
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return False
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def connect(self):
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"""建立与PLC的连接并验证"""
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current_time = time.time()
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# 指数退避重试
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if self.retry_count > 0:
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delay = min(self.retry_base_delay * (2 ** (self.retry_count - 1)), 30)
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if current_time - self.last_connect_attempt < delay:
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return False # 未到重试时间
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self.last_connect_attempt = current_time
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try:
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self.client.connect(self.ip, self.rack, self.slot)
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# 验证连接是否真正有效
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if self.client.get_connected() and self.is_valid_connection():
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self.connected = True
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self.retry_count = 0 # 重置重试计数
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self.logger.info(f"Successfully connected to PLC {self.ip}")
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return True
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else:
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self.connected = False
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self.logger.warning(f"Connection to {self.ip} established but PLC is not responding")
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try:
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self.client.disconnect()
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except:
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pass
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return False
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except Exception as e:
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self.retry_count = min(self.retry_count + 1, self.max_retries)
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self.logger.error(f"Connection to {self.ip} failed (attempt {self.retry_count}/{self.max_retries}): {e}")
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self.connected = False
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return False
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def read_db(self, db_number, offset, size):
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"""
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从DB块读取数据
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Args:
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db_number: DB编号
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offset: 起始偏移量
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size: 读取字节数
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Returns:
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bytearray: 读取的数据，如果失败返回None
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"""
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if not self.connected and not self.connect():
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self.logger.warning(f"Read failed: not connected to {self.ip}")
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return None # 返回None而不是零填充数据
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try:
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with self.lock: # 进入锁，其他线程需等待
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data = self.client.db_read(db_number, offset, size)
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# 验证返回数据的有效性
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if data is None or len(data) != size:
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self.connected = False
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self.logger.error(f"Read DB{db_number} returned invalid data size (expected {size}, got {len(data) if data else 0})")
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return None
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return data
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except Exception as e:
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self.logger.error(f"Read DB{db_number} error: {e}")
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self.connected = False
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return None
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def read_db_bool(self, db_number, offset, bit_length):
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"""
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从 DB 块中读取一个字节，并提取其中的多个 BOOL 位
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Args:
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db_number (int): DB块编号
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offset (int): 要读取的字节偏移地址
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bit_length: 第几位，如1，表示第1位
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Returns:
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result:返回位值
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"""
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if not self.connected and not self.connect():
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self.logger.warning(f"Read failed: not connected to {self.ip}")
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return None # 返回None而不是零填充数据
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try:
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with self.lock:
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data = self.client.db_read(db_number, offset, 1)
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result = {}
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for bit in range(bit_length):
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result[bit] = bool(data[0] & (1 << bit))
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if result is None or len(result) != bit_length:
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self.connected = False
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self.logger.error(f"Read DB{db_number} returned invalid data size (expected {bit_length}, got {len(result) if data else 0})")
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return None
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return result
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except Exception as e:
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self.logger.error(f"Read DB{db_number} error: {e}")
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self.connected = False
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return None
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def write_db(self, db_number, offset, data):
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"""
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向DB块写入数据
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Args:
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db_number: DB编号
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offset: 起始偏移量
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data: 要写入的数据
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Returns:
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bool: 是否写入成功
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"""
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if not self.connected and not self.connect():
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self.logger.warning(f"Write failed: not connected to {self.ip}")
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return False
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try:
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with self.lock:
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values = int(data)
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value = bytearray(0)
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if isinstance(values, int):
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set_int(value, offset, values)
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data = value
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self.client.db_write(db_number, offset, data)
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self.logger.debug(f"Wrote {len(data)} bytes to DB{db_number} offset {offset}")
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return True
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except Exception as e:
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self.logger.error(f"Write DB{db_number} error: {e}")
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self.connected = False
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return False
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def batch_write_db(self, db_number, offset, data):
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"""
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向DB块写入数据
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Args:
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db_number: DB编号
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offset: 起始偏移量
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data: 要写入的数据
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Returns:
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bool: 是否写入成功
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"""
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if not self.connected and not self.connect():
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self.logger.warning(f"Write failed: not connected to {self.ip}")
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return False
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try:
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with self.lock:
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self.client.db_write(db_number, offset, data)
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self.logger.debug(f"Wrote {len(data)} bytes to DB{db_number} offset {offset}")
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return True
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except Exception as e:
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self.logger.error(f"Write DB{db_number} error: {e}")
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self.connected = False
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return False
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def write_db_bool(self, db_number, offset, data):
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"""
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向DB块写入数据
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Args:
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db_number: DB编号
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offset: 起始偏移量
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data: 要写入的bool类型数据
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Returns:
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bool: 是否写入成功
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"""
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if not self.connected and not self.connect():
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self.logger.warning(f"Write failed: not connected to {self.ip}")
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return False
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try:
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with self.lock:
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data = data.decode('utf-8')
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# 将字符串安全转换为字典
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data_dict = ast.literal_eval(data) # 输出: {0: True}
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value = bytearray(offset + 1)
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for bit, val in data_dict.items():
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set_bool(value, offset, bit, val)
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data = value
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self.client.db_write(db_number, offset, data)
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self.logger.debug(f"Wrote {len(data)} bytes to DB{db_number} offset {offset}")
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return True
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except Exception as e:
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self.logger.error(f"Write DB{db_number} error: {e}")
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self.connected = False
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return False
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def batch_write_db_bool(self, db_number, offset, data):
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"""
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向DB块写入数据
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Args:
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db_number: DB编号
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offset: 起始偏移量
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data: 要写入的bool类型数据
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Returns:
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bool: 是否写入成功
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"""
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if not self.connected and not self.connect():
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self.logger.warning(f"Write failed: not connected to {self.ip}")
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return False
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try:
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with self.lock:
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print(db_number, offset, data)
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self.client.db_write(db_number, offset, data)
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self.logger.debug(f"Wrote {len(data)} bytes to DB{db_number} offset {offset}")
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return True
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except Exception as e:
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self.logger.error(f"Write DB{db_number} error: {e}")
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self.connected = False
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return False |