### 实现 ZLG USBCAN-Ⅱ+ 的 CAN 报文收发 在 Python 中使用 `zlgcan.dll` 实现 ZLG USBCAN-Ⅱ+ 设备的 CAN 报文收发，需要借助 `ctypes` 模块加载 DLL 并调用其函数。以下是一个完整的实现示例，涵盖了设备初始化、报文发送和接收的基本流程。 #### 加载 DLL 和定义结构体 为了调用 DLL 中的函数，首先需要加载 `zlgcan.dll`。由于该 DLL 可能依赖 Microsoft Visual C++ 运行库，因此需确保系统中已安装相应版本的运行库[^1]。 ```python import os from ctypes import WinDLL, Structure, c_uint, c_ushort, c_byte, c_int, POINTER, byref # 获取当前脚本所在目录 root = os.path.dirname(os.path.realpath(__file__)) # 指定 DLL 路径 dll_path = os.path.join(root, "zlgcan.dll") # 添加 DLL 所在目录到系统路径 dll_dir = os.path.dirname(dll_path) os.environ['PATH'] = dll_dir + ';' + os.environ['PATH'] # 加载 DLL can_dll = WinDLL(dll_path) if not can_dll: raise Exception("Failed to load zlgcan.dll") ``` 接下来定义 CAN 报文结构体 `VCI_CAN_OBJ`，该结构体用于存储 CAN 帧的 ID、时间戳、数据等信息： ```python class VCI_CAN_OBJ(Structure): _fields_ = [ ("ID", c_uint), ("TimeStamp", c_uint), ("TimeFlag", c_byte), ("SendType", c_byte), ("RemoteFlag", c_byte), ("ExternFlag", c_byte), ("DataLen", c_byte), ("Data", c_byte * 8), ("Reserved", c_byte * 3), ] ``` #### 初始化设备并配置 CAN 通道 使用 `VCI_OpenDevice` 打开设备，并通过 `VCI_InitCAN` 配置 CAN 通道的波特率等参数： ```python # 打开设备 result = can_dll.VCI_OpenDevice(4, 0, 0) # 设备类型为 USBCAN-Ⅱ+ if result != 1: raise Exception("Failed to open device") # 定义 CAN 初始化结构体 class VCI_INIT_CONFIG(Structure): _fields_ = [ ("AccCode", c_uint), ("Mask", c_uint), ("Reserved", c_uint), ("Filter", c_byte), ("Timing0", c_byte), ("Timing1", c_byte), ("Mode", c_byte), ] # 配置 CAN 通道 init_config = VCI_INIT_CONFIG() init_config.AccCode = 0x00000000 init_config.Mask = 0xFFFFFFFF init_config.Filter = 0 init_config.Timing0 = 0x00 # 波特率配置 init_config.Timing1 = 0x1C init_config.Mode = 0 # 正常模式 result = can_dll.VCI_InitCAN(4, 0, 0, byref(init_config)) if result != 1: raise Exception("Failed to initialize CAN channel") ``` #### 启动 CAN 通道并发送报文 启动 CAN 通道后，即可调用 `VCI_Transmit` 发送 CAN 报文： ```python # 启动 CAN 通道 result = can_dll.VCI_StartCAN(4, 0, 0) if result != 1: raise Exception("Failed to start CAN channel") # 准备发送的 CAN 报文 can_obj = VCI_CAN_OBJ() can_obj.ID = 0x123 can_obj.DataLen = 8 can_obj.ExternFlag = 0 # 标准帧 can_obj.RemoteFlag = 0 # 数据帧 for i in range(8): can_obj.Data[i] = i # 发送报文 result = can_dll.VCI_Transmit(4, 0, 0, byref(can_obj), 1) if result != 1: raise Exception("Failed to send CAN message") ``` #### 接收 CAN 报文 调用 `VCI_Receive` 接收 CAN 报文，并打印相关信息： ```python # 接收报文 recv_obj = (VCI_CAN_OBJ * 1)() result = can_dll.VCI_Receive(4, 0, 0, byref(recv_obj), 1, 1000) if result > 0: print(f"Received message ID: {recv_obj[0].ID}") print(f"Data: {[recv_obj[0].Data[i] for i in range(recv_obj[0].DataLen)]}") else: print("No message received") ``` #### 完整示例代码 以下为完整的 Python 示例代码，用于打开设备、配置 CAN 通道、发送和接收 CAN 报文： ```python import os from ctypes import WinDLL, Structure, c_uint, c_ushort, c_byte, c_int, POINTER, byref # 获取当前脚本所在目录 root = os.path.dirname(os.path.realpath(__file__)) dll_path = os.path.join(root, "zlgcan.dll") # 添加 DLL 所在目录到系统路径 dll_dir = os.path.dirname(dll_path) os.environ['PATH'] = dll_dir + ';' + os.environ['PATH'] # 加载 DLL can_dll = WinDLL(dll_path) if not can_dll: raise Exception("Failed to load zlgcan.dll") # 定义 CAN 报文结构体 class VCI_CAN_OBJ(Structure): _fields_ = [ ("ID", c_uint), ("TimeStamp", c_uint), ("TimeFlag", c_byte), ("SendType", c_byte), ("RemoteFlag", c_byte), ("ExternFlag", c_byte), ("DataLen", c_byte), ("Data", c_byte * 8), ("Reserved", c_byte * 3), ] # 定义 CAN 初始化结构体 class VCI_INIT_CONFIG(Structure): _fields_ = [ ("AccCode", c_uint), ("Mask", c_uint), ("Reserved", c_uint), ("Filter", c_byte), ("Timing0", c_byte), ("Timing1", c_byte), ("Mode", c_byte), ] # 打开设备 result = can_dll.VCI_OpenDevice(4, 0, 0) if result != 1: raise Exception("Failed to open device") # 配置 CAN 通道 init_config = VCI_INIT_CONFIG() init_config.AccCode = 0x00000000 init_config.Mask = 0xFFFFFFFF init_config.Filter = 0 init_config.Timing0 = 0x00 init_config.Timing1 = 0x1C init_config.Mode = 0 result = can_dll.VCI_InitCAN(4, 0, 0, byref(init_config)) if result != 1: raise Exception("Failed to initialize CAN channel") # 启动 CAN 通道 result = can_dll.VCI_StartCAN(4, 0, 0) if result != 1: raise Exception("Failed to start CAN channel") # 发送报文 can_obj = VCI_CAN_OBJ() can_obj.ID = 0x123 can_obj.DataLen = 8 can_obj.ExternFlag = 0 can_obj.RemoteFlag = 0 for i in range(8): can_obj.Data[i] = i result = can_dll.VCI_Transmit(4, 0, 0, byref(can_obj), 1) if result != 1: raise Exception("Failed to send CAN message") # 接收报文 recv_obj = (VCI_CAN_OBJ * 1)() result = can_dll.VCI_Receive(4, 0, 0, byref(recv_obj), 1, 1000) if result > 0: print(f"Received message ID: {recv_obj[0].ID}") print(f"Data: {[recv_obj[0].Data[i] for i in range(recv_obj[0].DataLen)]}") else: print("No message received") ``` ###