from pymodbus.client.sync import ModbusTcpClient

from pymodbus.exceptions import ConnectionException

def read_holding_registers(ip, port, start_address, count):

"""

读取Modbus TCP服务器上的保持寄存器

:param ip: Modbus服务器的IP地址

:param port: Modbus服务器的端口号

:param start_address: 要读取的寄存器的起始地址

:param count: 要读取的寄存器数量

:return: 寄存器值的列表

"""

try:

# 连接到Modbus服务器

client = ModbusTcpClient(ip, port=port)

connection = client.connect()

if connection:

# 读取保持寄存器

result = client.read_holding_registers(start_address, count)

if not result.isError():

# 转换并返回寄存器值

return [reg.value for reg in result.registers]

else:

print("读取失败：", result)

else:

print("连接失败")

except ConnectionException as e:

print("连接异常：", e)

except Exception as e:

print("发生错误：", e)

finally:

# 关闭连接

client.close()

return []

# 使用示例

if __name__ == "__main__":

ip = "192.168.1.100"

port = 502

start_address = 0

count = 10

registers = read_holding_registers(ip, port, start_address, count)

if registers:

print("读取的寄存器值：", registers)

from pymodbus.server.sync import StartTcpServer

from pymodbus.datastore import ModbusSlaveContext, ModbusServerContext

from pymodbus.datastore import ModbusHoldingRegisters

def run_modbus_server(address=("localhost", 5020)):

"""

运行Modbus TCP服务器

:param address: 服务器的地址和端口

"""

# 初始化寄存器

holding_registers = ModbusHoldingRegisters()

holding_registers[0] = 10 # 示例：设置寄存器0的值为10

holding_registers[1] = 20

# 创建从站上下文

slave_context = ModbusSlaveContext(

di=None,

co=None,

hr=holding_registers,

ir=None,

zero_mode=True

)

# 创建服务器上下文

context = ModbusServerContext(slaves={1: slave_context}, single=True)

# 运行服务器

StartTcpServer(context, address=address)

# 你可以通过运行这个函数来启动一个Modbus TCP服务器，并在另一个脚本中作为客户端连接它

# if __name__ == "__main__":

# run_modbus_server()