import concurrent.futures import time import logging import socket import struct import binascii # modbus tcp client class ModbusTCPClient: def __init__(self, ip, port): self.ip = ip self.port = port self.socket = None def connect(self): self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) self.socket.connect((self.ip, self.port)) def disconnect(self): self.socket.close() self.socket = None def read_registers(self, start_addr, count): request = struct.pack('>HHHH', 0x0001, start_addr, count, 0x0000) self.socket.send(request) response = self.socket.recv(1024) return struct.unpack_from('>' + 'H' * count, response, offset=9) def write_register(self, addr, value): request = struct.pack('>HHH', 0x0006, addr, value) self.socket.send(request) response = self.socket.recv(1024) return struct.unpack_from('>HH', response, offset=9) # worker function for thread pool def worker(ip, port, start_addr, count): client = ModbusTCPClient(ip, port) client.connect() try: # read registers values = client.read_registers(start_addr, count) logging.info('ip=%s, values=%s', ip, values) # write a value client.write_register(start_addr, 0x1234) except Exception as e: logging.error('ip=%s, error=%s', ip, str(e)) finally: client.disconnect() # main function def main(): # configure logging logging.basicConfig(level=logging.INFO, format='%(asctime)s %(levelname)s %(message)s') # list of modbus tcp devices devices = [ {'ip': '127.0.0.1', 'port': 502, 'start_addr': 0, 'count': 2}, {'ip': '127.0.0.1', 'port': 503, 'start_addr': 2, 'count': 2}, {'ip': '127.0.0.1', 'port': 504, 'start_addr': 4, 'count': 2}, ] # create thread pool with concurrent.futures.ThreadPoolExecutor(max_workers=len(devices)) as executor: # submit tasks to thread pool futures = [executor.submit(worker, device['ip'], device['port'], device['start_addr'], device['count']) for device in devices] # wait for tasks to complete for future in concurrent.futures.as_completed(futures): try: future.result() except Exception as e: logging.error('error=%s', str(e)) # entry point if __name__ == '__main__': main() 数据包多少
时间: 2024-04-03 20:32:10 浏览: 22
根据代码,数据包的大小是13个字节。对于读取寄存器的请求,使用了struct.pack('>HHHH', 0x0001, start_addr, count, 0x0000)打包成13个字节的请求数据包,其中'>HHHH'表示4个大端无符号short类型数据。对于写入寄存器的请求,使用了struct.pack('>HHH', 0x0006, addr, value)打包成9个字节的请求数据包,其中'>HHH'表示3个大端无符号short类型数据。因此,数据包的大小是13个字节或9个字节,取决于请求类型。
相关问题
from concurrent.futures import ThreadPoolExecutor举例
ThreadPoolExecutor是Python标准库concurrent.futures中的一个类,用于创建一个线程池并在多个线程中执行任务。它提供了一种简单而高效的方式来并发执行多个任务。
下面是一个使用ThreadPoolExecutor的示例:
```python
import concurrent.futures
# 定义一个任务函数
def task(num):
print(f"Executing task {num}")
result = num * 2
print(f"Task {num} result: {result}")
return result
# 创建一个ThreadPoolExecutor对象
with concurrent.futures.ThreadPoolExecutor() as executor:
# 提交任务给线程池执行,并返回一个Future对象
future1 = executor.submit(task, 1)
future2 = executor.submit(task, 2)
# 获取任务的执行结果
result1 = future1.result()
result2 = future2.result()
print(f"Task 1 result: {result1}")
print(f"Task 2 result: {result2}")
```
以上代码会创建一个线程池,并在两个线程中分别执行任务task(1)和task(2)。每个任务都会打印出执行过程和结果,并通过future.result()获取到任务的返回值。
from concurrent.futures.thread import ThreadPoolExecutor
from concurrent.futures.thread模块中的ThreadPoolExecutor是用于创建线程池的类。通过导入ThreadPoolExecutor,我们可以使用线程池来并发执行多个任务。线程池中的线程会在后台自动创建和销毁,并且可以重复利用,从而提高程序的效率。通过使用ThreadPoolExecutor类,我们可以方便地管理和控制线程的数量和任务的执行。<span class="em">1</span><span class="em">2</span><span class="em">3</span>
#### 引用[.reference_title]
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