Python-CAN脚本接收一半预期的CAN消息

Question

我使用Python库编写了一个Python脚本，该库以1秒的速度记录接收到的CAN消息5分钟，然后将所有消息记录到文件中并退出。计算机具有连接到CAN总线的CAN模块。(总线上的另一个设备是引擎)我使用SocketCAN接口与它通信。

这台计算机连接的测试引擎系统以250 at的波特率发送了大约114条消息。我期望看到每1秒记录在文件中的114条消息，但是我却看到了大约一半的记录。(~65条信息)

是否有可能引擎的ECU被设置为500 am的波特率，这就是为什么我没有得到我预期的计数？我认为如果波特率不匹配，就不会有通信，但我没有对系统的物理访问，因为我正在通过OTA更新远程发送脚本，而不是亲自运行它。(设备是无头的，但设置是在启动时运行脚本)，我只看到生成的日志文件。

下面是python代码：

(注意，我有将接收到的消息解析为包含的信号的代码，但是我在这里没有包含这段代码，因为它发生在末尾，而且与此无关)

class logging:

    def __init__(self):
        #Dictionary to hold received CAN messages
        self.message_Dict = {}

        #List to hold queued dictionaries
        self.message_Queue = []

        #A "filters" object is also created here, but I did not include it
        #I have verified the filters are correct on my test system

    def main(self):

        #Record the current time
        currentTime = datetime.datetime.now()

        #Record the overall start time
        startTime = datetime.datetime.now()

        #Record the iteration start time
        lastIterationStartTime = currentTime

        #Create the CanBus that will be used to send and receive CAN msgs from the MCU
        canbus = can.interfaces.socketcan.SocketcanBus(channel='can0', bitrate=250000)
        #These filters are setup correctly, because all the messages come through
        #on my test system, but I did not include them here
        canbus.set_filters(self.Filters)

        # Creating Listener filters and notifier
        listener = can.Listener()

        #Main loop
        while 1:        

            #create a variable to hold received data
            msg2 = canbus.recv()

            #Record the current time
            currentTime = datetime.datetime.now()

            #If a valid message is detected
            if(msg2 != None):
               if(len(msg2.data) > 0):
                   try:                                
                       #Save the message data into a queue (will be processed later)
                       self.message_Dict[msg2.arbitration_id] = msg2.data

                   except:
                       print("Error in storing CAN message")

            #If 1 second has passed since the last iteration, 
            #add the dictionary to a new spot in the queue
            if((currentTime - lastIterationStartTime) >= datetime.timedelta(seconds=1)):

                #Add the dictionary with messages into the queue for later processing
                messageDict_Copy = self.message_Dict.copy()
                self.message_Queue.append(messageDict_Copy)

                print("Number of messages in dictionary: " + str(len(self.message_Dict)) + " 
                   Number of reports in queue: " + str(len(self.message_Queue)))

                #Clear the dictionary for new messages for every iteration
                self.message_Dict.clear()

                #Record the reset time
                lastIterationStartTime = datetime.datetime.now()
            
            #Once 5 minutes of data has been recorded, write to the file
            if((currentTime - startTime) > datetime.timedelta(minutes=5)):
                
                #Here is where I write the data to a file. This is too long to include

                #Clear the queue
                self.message_Queue = []

                #Clear the dictionary for new messages for every iteration
                self.message_Dict.clear()

#When the script is run, execute the Main method
if __name__ == '__main__':  
    mainClass = logging()
    mainClass.main()

我很感激你的任何想法或意见。谢谢

Answer 1

根据我的经验，大多数发动机的ECU通常使用250 my，但最新的使用500 my。我建议你也试试这两种。

此外，消息只有在被发送时才会到达总线上，这似乎很愚蠢，但是，例如，一辆卡车，如果您不踩上加速器，就不会出现涉及加速器的消息。因此，您可能需要检查是否所有组件都按照您的预期使用。罐用库有一个“can嗅探器”，它也可以帮助您。

我建议你用“可以-利用”来帮助你。它是一个强大的工具，可以进行分析。

你有没有试着循环波德率？也许也能帮你找到另一个。