Index: /trunk/Mars/mdrs/MDrsCalibApply.cc
===================================================================
--- /trunk/Mars/mdrs/MDrsCalibApply.cc	(revision 19857)
+++ /trunk/Mars/mdrs/MDrsCalibApply.cc	(revision 19858)
@@ -129,4 +129,18 @@
     }
 
+    if (fSignal->GetNumPixels()%9)
+    {
+        *fLog << warn << "MPedestalSubtractedEvt size [" << fSignal->GetNumPixels() << "] not a multiple of 9...";
+        *fLog << "step correction will not be applied." << endl;
+    }
+    else
+    {
+        if (fSignal->GetNumPixels()!=fRawEvt->GetNumPixels())
+        {
+            *fLog << warn << "MPedestalSubtractedEvt size [" << fSignal->GetNumPixels() << "] does not match raw data [" << fRawEvt->GetNumPixels() << "]...";
+            *fLog << "step correction might not work properly if mapping table exceeds " << fSignal->GetNumPixels() << endl;
+        }
+    }
+
     return kTRUE;
 }
@@ -224,5 +238,5 @@
     }
 
-    if (fResult)
+    if (fResult && fSignal->GetNumPixels()%9==0)
     {
         fResult->fData.resize(fPrevStart.size()*2);