--- DarthVader/TrackerLevel2/src/F77/functions.f	2007/04/27 12:11:03	1.3
+++ DarthVader/TrackerLevel2/src/F77/functions.f	2007/05/24 16:45:48	1.4
@@ -358,10 +358,25 @@
 
       dcoord=0.
       
+      if(
+     $     ladder.lt.1.or.
+     $     ladder.gt.nladders_view.or.
+     $     sen.lt.1.or.
+     $     sen.gt.2.or.
+     $     view.lt.1.or.
+     $     view.gt.nviews.or.
+     $     .false.)then
+         print*,'dcoord ---> wrong input: ladder ',ladder
+     $        ,' sensor ',sen
+     $        ,' view ',view
+         return
+      endif
+
       sx=ladder
       sy=sen
       sz=npl(view)
 
+
       if(mod(view,2).eq.0) then !X view
 
         trasl=x_mech_sensor(sz,sx,sy) !in mm