Index: /trunk/FACT++/src/DataWriteFits2.cc
===================================================================
--- /trunk/FACT++/src/DataWriteFits2.cc	(revision 17275)
+++ /trunk/FACT++/src/DataWriteFits2.cc	(revision 17276)
@@ -179,4 +179,21 @@
         Error("ofits - file '"+fFileName+"' already exists.");
         return false;
+    }
+
+    zofits *fits = dynamic_cast<zofits*>(fFile.get());
+    if (fits)
+    {
+        // Maximum number of tiles setup by user
+        uint32_t num = zofits::DefaultMaxNumTiles();
+
+        // Maximum number if data is taken with 100Hz
+        if (d.maxtime*100<num)
+            num = d.maxtime*100/zofits::DefaultNumRowsPerTile()+1;
+
+        // Maximum number if number is known
+        if (d.maxevt<num)
+            num = d.maxevt/zofits::DefaultNumRowsPerTile()+1;
+
+        fits->SetNumTiles(num);
     }