PROSAGA码农传奇-MQTT/MODBUS-使用Pymodbus将RS232 Ascii转换为Modbus TCP

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    你需要的是什么
    <a href="https://github.com/riptideio/pymodbus/blob/master/examples/common/updating_server.py" rel="nofollow noreferrer">
      更新服务器
    </A>
    ，您可以用来填充寄存器。你将不得不专注于功能
     <code>
 def updating_writer
 </code>
     并执行串行读取，处理它们并写入您选择的寄存器。这个例子很难在第一时间阅读和理解。我修改了
    <a href="https://gist.github.com/dhoomakethu/540b15781c62de6d1f7c318c3fc8ae22" rel="nofollow noreferrer">
      例
    </A>
     满足您的需求。但是这里有一些关键概念可以方便地理解代码。
  
  
    <a href="https://pymodbus.readthedocs.io/en/latest/source/library/pymodbus.datastore.html#pymodbus.datastore.context.ModbusSlaveContext" rel="nofollow noreferrer">
      ModbusSlaveContext
    </A>
  
  
    <a href="https://pymodbus.readthedocs.io/en/latest/source/library/pymodbus.html#pymodbus.payload.BinaryPayloadBuilder" rel="nofollow noreferrer">
      BinaryPayloadBuilder
    </A>
  
  
    另请注意，该示例使用基于twisted的异步服务器，如果您是新手，或者有一些限制，不允许您在目标上使用扭曲，您也可以通过简单的线程实现相同。设计大致是这样的。
  
  <OL>
    <LI>
      在单独的线程中启动更新功能
    </LI>
    <LI>
      最后启动TCP服务器（阻止）
    </LI>
  </醇>
   <pre>
 <code>
 # Complete gist here --> https://gist.github.com/dhoomakethu/540b15781c62de6d1f7c318c3fc8ae22
def updating_writer(context, device, baudrate):
 """ A worker process that runs every so often and
 updates live values of the context. It should be noted
 that there is a race condition for the update.
 :param arguments: The input arguments to the call
 """
 log.debug("updating the context")
 log.debug("device - {}, baudrate-{}".format(device, baudrate))
 data = serial_reader(device, baudrate) # Implement your serial reads, return list of floats.
 if data:
 # We can not directly write float values to registers, Use BinaryPayloadBuilder to convert float to IEEE-754 hex integer
 for d in data:
 builder.add_32bit_float(d)
 registers = builder.to_registers()
 context = context
 register = 3 # Modbus function code (3) read holding registers. Just to uniquely identify what we are reading from /writing in to.
 slave_id = 0x01 # Device Unit address , refer ModbusSlaveContext below
 address = 0x00 # starting offset of register to write (0 --> 40001)
 log.debug("new values: " + str(registers))
 context[slave_id].setValues(register, address, registers)

</code>
 </pre>
  
    一旦服务器运行并且值正在更新，您可以使用客户端读取值并将其解析回浮动。
  
   <pre>
 <code>
 from pymodbus.client.sync import ModbusTcpClient as Client
from pymodbus.payload import BinaryPayloadDecoder, Endian
client = Client(<IP-ADDRESS>, port=5020)

# Each 32 bit float is stored in 2 words, so we will read 10 registers 
raw_values = client.read_holding_registers(0, 10, unit=1)
if not registers.isError():
    registers = raw_values.registers
    decoder = BinaryPayloadDecoder.fromRegisters(registers, 
    wordorder=Endian.Big, byteorder=Endian.Big)

for _ in range(5):
        print(decoder.decode_32bit_float())

</code>
 </pre>
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