fix：“设备异常离线检测改成每半个小时检测一次“

src/main/java/com/szwl/controller/ScheduledService.java

@@ -145,7 +145,7 @@ public class ScheduledService {
     }
 
     // 设备状态检测
-    @Scheduled(cron = "0 30 * * * ?")
+    @Scheduled(cron = "0 */30 * * * ?")
     public void checkEquipmentStatus() {
         if (isDo()) {
             equipmentService.checkEquipmentStatus();