您会收到此错误：

AttributeError: 'ModbusTcpClient' object has no attribute 'modbus'

因为当您建立的Thread：
t2 = threading.Thread(target=control, args=(client, 'get'))
调用Temperature_Controll2.temp_controll(client, 'get')，
在这一行：rp = self.modbus.read_coils(524, 0x1)self实际上是您在此处创建的client变量：
with ModbusClient(host=HOST, port=PORT) as client:
而不是您所期望的Temperature_Controll2的示例。

好了，再次感谢，解决的办法是：

class Temperature_Controll2(Echo):

    def __init__(self, client):
        #super(Temperature_Controll2, self).__init__() #client , server, sock, address, database_reading)
        #super().__init__()
        self.modbus = client

    def temp_controll(self, value):
        #super().temp_controll(client)
        while True:
            print("temp_controll")
            rp = self.modbus.read_coils(524, 0x1)
            time.sleep(4)

def main():
    with ModbusClient(host=HOST, port=PORT) as client:
        client.connect()
        time.sleep(0.01)

        print("Websocket server on port %s" % PORTNUM)
        server = SimpleWebSocketServer('', PORTNUM, partial(Echo, client))

        control = Temperature_Controll2(client)
        t2 = threading.Thread(target=control.temp_controll('get'))

        try:
            t1 = threading.Thread(target=server.serveforever())
            t1.start()
        finally:
            server.close()

但是对于客户端，我只能建立一个到modbus服务器的连接，所以WebSocket或者while循环都可以工作，我想我必须用不同的方法来解决这个问题。

一个简短的增编，我想，我现在知道为什么第二个变体不起作用了。
这个变量一直在运行，直到类Echo中的temp_control到达一个点，其中modbus模块被一个函数调用。Modbus模块不是母类Echo的一部分，这就是为什么我认为这不能被继承。
Modbus作为变量通过partial传递给类Echo，因此将示例化（我希望我的表达是正确的）。因此，只有变量client传递给示例的变体才能工作。

# This is a non-functional version of my programme and is for information only

class Echo(WebSocket):

    def __init__(self, client, server, sock, address):
        super().__init__(server, sock, address)
        self.modbus = client

    def temp_control(self)
        do_something()
        return True

class Temperature_Control3(Echo):

    def __init__(self, value=None): #, client, server, sock, address):
        #super(Temperature_Control3, self).__init__(server, sock, address) 
        if value is None:
            value = {}
        self.value = value

    def control(self, value):
        while True:
            self.temp_control(524, 'get')
            #self.database_reading()[0][1]
            time.sleep(2)

def main():
    with ModbusClient(host=HOST, port=PORT) as client:
        client.connect()
        time.sleep(0.01)

        print("Websocket server on port %s" % PORTNUM)
        server = SimpleWebSocketServer('', PORTNUM, partial(Echo, client))

        control = Temperature_Control3()

        t3 = threading.Thread(target=lambda:control.control('get')) 
        t3.start()

        try:
            t1 = threading.Thread(target=server.serveforever())
            t1.start()
            for thread in threading.enumerate():
                print(thread.name)
        finally:
            server.close()