diff --git a/src/src/main/java/com/my/graphiteDigesterBg/task/TaskDigestion.java b/src/src/main/java/com/my/graphiteDigesterBg/task/TaskDigestion.java
index a0760aa..ce4268f 100644
--- a/src/src/main/java/com/my/graphiteDigesterBg/task/TaskDigestion.java
+++ b/src/src/main/java/com/my/graphiteDigesterBg/task/TaskDigestion.java
@@ -4,6 +4,7 @@ import com.my.graphiteDigesterBg.diframe.DiTaskStepTaskBase;
 import com.my.graphiteDigesterBg.diframe.Task;
 import com.my.graphiteDigesterBg.model.MdbDigestionTask;
 import com.my.graphiteDigesterBg.model.MdbOperationLog;
+import com.my.graphiteDigesterBg.resource.ResHeatingTubeRackSlot;
 import com.my.graphiteDigesterBg.resource.ResHeatingTubeRackSlotManager;
 
 import java.util.Map;
@@ -13,6 +14,8 @@ public class TaskDigestion extends DiTaskStepTaskBase {
     public Integer id;
     // slot index
     public Integer slotIndex;
+    // slot
+    private ResHeatingTubeRackSlot slot;
 
     @Override
     protected void setup() {
@@ -22,8 +25,8 @@ public class TaskDigestion extends DiTaskStepTaskBase {
         }
 
         var slotMan = this.getResourceManager(ResHeatingTubeRackSlotManager.class);
-        var slot = slotMan.getSlotByIndex(this.slotIndex);
-        slot.digestionName = taskModel.name;
+        this.slot = slotMan.getSlotByIndex(this.slotIndex);
+        this.slot.digestionName = taskModel.name;
 
         this.loadStepsByJson(taskModel.steps);
 
@@ -32,8 +35,22 @@ public class TaskDigestion extends DiTaskStepTaskBase {
 
     @Override
     protected void afterRun() {
-        var slotMan = this.getResourceManager(ResHeatingTubeRackSlotManager.class);
-        var slot = slotMan.getSlotByIndex(this.slotIndex);
-        slot.digestionName = null;
+        this.slot.digestionName = null;
+    }
+
+    @Override
+    protected void onError( Exception e ) {
+        this.slot.digestionName = null;
+    }
+
+    // throw exception
+    public void throwException(String message) {
+        String msg = String.format("[试管架%d - %s] : %s", this.slotIndex, this.slot.digestionName, message);
+        throw new RuntimeException(msg);
+    }
+
+    // get slot
+    public ResHeatingTubeRackSlot getSlot() {
+        return this.slot;
     }
 }