Question

我正在使用pymodbus库来创建Modbus服务器。我发现了你可以找到的所有例子here。我遇到了与在服务器（从属）端写入浮点值有关的问题。有一个updating_writer函数，我想在其中将float值= 22.34写入2个持有resitors：

...
    def updating_writer(a):
        context  = a[0]
        register = 3
        slave_id = 0x00
        address  = 0x0
        builder = BinaryPayloadBuilder(endian=Endian.Little)
        builder.add_32bit_float(22.34)
        res = builder.build()
        context[slave_id].setValues(register, address, res)

    store = ModbusSlaveContext(
        di = ModbusSequentialDataBlock(0, [17]*100),
        co = ModbusSequentialDataBlock(0, [17]*100),
        hr = ModbusSequentialDataBlock(0, [17]*100),
        ir = ModbusSequentialDataBlock(0, [17]*100))
    context = ModbusServerContext(slaves=store, single=True)
...

但是当我从Modbus主站（客户端）连接并尝试读取这2个registor时出现错误：

...
    File "/home/workstation/devel/modbus_example/env_modbus/local/lib/python2.7/site-packages/pymodbus/server/async.py", line 83, in _send
        pdu = self.framer.buildPacket(message)
      File "/home/workstation/devel/modbus_example/env_modbus/local/lib/python2.7/site-packages/pymodbus/transaction.py", line 354, in buildPacket
        data = message.encode()
      File "/home/workstation/devel/modbus_example/env_modbus/local/lib/python2.7/site-packages/pymodbus/register_read_message.py", line 71, in encode
        result += struct.pack('>H', register)
    struct.error: cannot convert argument to integer

我应该如何将float值写入某些上下文？我找不到任何例子。

将浮点值写入ModbusServerContext

0 个答案: