更新

WindowsFormsApp6/MainForm.cs

@@ -26,6 +26,11 @@ namespace WindowsFormsApp6
         private SerialPort _serialPort;
         private IModbusMaster _modbusMaster;
         private System.Windows.Forms.Timer _readTimer;
+        
+        // 超时计数器
+        private int _timeoutCount = 0;
+        private const int MAX_TIMEOUT_COUNT = 5; // 连续超时5次后提示
+        private bool _isClosing = false; // 标记是否正在关闭
 
         // Form1历史数据缓存（用于累积显示）
         private List<double> form1TimeValues = new List<double>();
@@ -242,7 +247,7 @@ namespace WindowsFormsApp6
         /// </summary>
         private void ReadTimer_Tick(object sender, EventArgs e)
         {
-            if (_modbusMaster == null || _serialPort == null || !_serialPort.IsOpen)
+            if (_isClosing || _modbusMaster == null || _serialPort == null || !_serialPort.IsOpen)
                 return;
 
             try
@@ -281,13 +286,59 @@ namespace WindowsFormsApp6
                     // 读取完成后清除信号量
                     WriteCoil(slaveId, 310, false);
                 }
+                
+                // 通信成功，重置超时计数器
+                _timeoutCount = 0;
+            }
+            catch (TimeoutException tex)
+            {
+                // 超时异常处理
+                _timeoutCount++;
+                System.Diagnostics.Debug.WriteLine($"Modbus通信超时（{_timeoutCount}/{MAX_TIMEOUT_COUNT}）：{tex.Message}");
+                
+                if (_timeoutCount >= MAX_TIMEOUT_COUNT)
+                {
+                    HandleCommunicationTimeout();
+                }
             }
             catch (Exception ex)
             {
-                // 读取失败时不弹窗，避免频繁打扰用户
-                System.Diagnostics.Debug.WriteLine($"Modbus读取失败：{ex.Message}");
+                // 其他异常也计入超时
+                _timeoutCount++;
+                System.Diagnostics.Debug.WriteLine($"Modbus读取失败（{_timeoutCount}/{MAX_TIMEOUT_COUNT}）：{ex.Message}");
+                
+                if (_timeoutCount >= MAX_TIMEOUT_COUNT)
+                {
+                    HandleCommunicationTimeout();
+                }
             }
         }
+        
+        /// <summary>
+        /// 处理通信超时
+        /// </summary>
+        private void HandleCommunicationTimeout()
+        {
+            if (_isClosing) return;
+            
+            _isClosing = true;
+            
+            // 停止定时器
+            _readTimer?.Stop();
+            
+            // 在UI线程上显示提示并关闭
+            this.Invoke(new Action(() =>
+            {
+                MessageBox.Show(
+                    $"Modbus通信连续超时{MAX_TIMEOUT_COUNT}次，设备可能已断开连接。\n程序将自动关闭。",
+                    "通信超时",
+                    MessageBoxButtons.OK,
+                    MessageBoxIcon.Warning);
+                
+                // 关闭窗体
+                this.Close();
+            }));
+        }
 
         /// <summary>
         /// 读取单个线圈状态
@@ -299,6 +350,11 @@ namespace WindowsFormsApp6
                 bool[] coils = _modbusMaster.ReadCoils(slaveId, address, 1);
                 return coils[0];
             }
+            catch (TimeoutException)
+            {
+                // 超时异常向上抛出
+                throw;
+            }
             catch
             {
                 return false;
@@ -314,6 +370,12 @@ namespace WindowsFormsApp6
             {
                 _modbusMaster.WriteSingleCoil(slaveId, address, value);
             }
+            catch (TimeoutException tex)
+            {
+                System.Diagnostics.Debug.WriteLine($"写入线圈超时：{tex.Message}");
+                // 超时异常向上抛出
+                throw;
+            }
             catch (Exception ex)
             {
                 System.Diagnostics.Debug.WriteLine($"写入线圈失败：{ex.Message}");
@@ -2390,6 +2452,8 @@ namespace WindowsFormsApp6
 
         private void MainForm_FormClosing(object sender, FormClosingEventArgs e)
         {
+            _isClosing = true;
+            
             // 停止并释放定时器
             timeUpdateTimer?.Stop();
             timeUpdateTimer?.Dispose();