Question

在使用Python- Snap7读写数据到Siemens s7 1200 PLC的过程中，出现如下异常：

线程Thread-2中的异常：追溯（最近一次通话）： _bootstrap_inner中的第917行“ C：\ Users \ MDoganli \ AppData \ Local \ Programs \ Python \ Python37-32 \ Lib \ threading.py”文件 self.run（）运行中的文件“ C：\ Users \ MDoganli \ AppData \ Local \ Programs \ Python \ Python37-32 \ Lib \ threading.py”，行865 self._target（* self._args，** self._kwargs）在read_data中的第59行，文件“ C：\ Companies \ Personal \ deneme \ deneme_iterasyonlar \ plcman.py” 扭矩= plc.read_area（area ['DB']，110,80,24）文件“ C：\ Users \ MDoganli \ AppData \ Local \ Programs \ Python \ Python37-32 \ lib \ site-packages \ snap7 \ client.py”，行256，在read_area中 check_error（result，context =“ client”）文件“ C：\ Users \ MDoganli \ AppData \ Local \ Programs \ Python \ Python37-32 \ lib \ site-packages \ snap7 \ common.py”，第65行，在check_error中引发Snap7Exception（错误） snap7.snap7exceptions.Snap7Exception：b'CLI：作业待处理'

我在单通道db_read / db_write期间没有遇到此问题，但是在其他读取或写入通道处于活动状态时会发生。

我尝试了area_read和area_write以及db_read和db_write选项，但是收到类似的错误。

主要代码：

   plc=plcman.PLC_Controller('192.168.30.100',0,1)
   plc.connect()
   time.sleep(1)
   plc.start_thread2()
   time.sleep(1)
   plc.start_thread()

PLC数据读写代码

class PLC_Controller:

    plc=c.Client()
    def __init__(self, address, rack, slot):

        self.address = address
        self.rack = rack
        self.slot = slot


    def connect(self):

        count = 0

        if  plc.get_connected() == False:
            print("Try " + str(count) + " - Connecting to PLC: " +
                    self.address + ", Rack: " + str(self.rack) + ", Slot: " + str(self.slot))
            try:
                plc.connect(self.address, self.rack, self.slot) #('IP-address', rack, slot)
            except Exception as e:
                print(e)

        if  plc.get_connected() == True:
            return plc.get_connected() == True    

    def get_word(self,_bytearray, byte_index):
        data = _bytearray[byte_index:byte_index + 2]
        data=data[::-1]
        dword = struct.unpack('H', struct.pack('2B', *data))[0]
        return dword


    def read_data(self):

            torque=plc.read_area(areas['DB'],110,80,24)
            data1=self.get_word(torque,0)

            time.sleep(0.8)
            self.read_data()

    def start_thread(self):
        thread = threading.Thread(target=self.read_data, args=())
        thread.daemon = True
        thread.start()


    def set_word(self,_bytearray, byte_index, word):
        word=int(word)

        _bytes =  struct.pack('H', word)
        _bytes=_bytes[::-1]

        for i, b in enumerate(_bytes):
            time.sleep(1)

            _bytearray[byte_index + i] = b

         res=plc.write_area(areas['DB'],110,24,_bytearray)


    def start_thread2(self):

        thread = threading.Thread(target=self.stoprun, args=())
        thread.daemon = True
        thread.start()

    def stoprun(self):

        Lamp=4
        torque=plc.read_area(areas['DB'],110,80,24)
        val1=self.set_word(torque, 0, 8)
        self.stoprun()

谢谢。

Answer 1

读取和写入应具有不同的PLC连接实例。修改后的连接为：

 plc=plcman.PLC_Controller('192.168.30.100',0,1)   # for reading use plc.read_area()
 plc.connect()  
 plc2=plcman.PLC_Controller('192.168.30.100',0,1)
 plc2.connect()  #for writing use plc2.write_area()

最多允许3个实例。在读写过程中将不会收到“待处理的作业”

Snap7-Python数据读/写到PLC期间作业挂起异常

1 个答案: