diff --git a/code.fnl b/code.fnl
index 4a0914f..80fc8be 100644
--- a/code.fnl
+++ b/code.fnl
@@ -1,45 +1,55 @@
 (local depth 60)
-(local cable-dir "left")
-(local outputs {
-       :right 1
-       :left 2
-       :up 4
-       :down 8
-       :break 16
-       :rejuv 32})
+(local cable-dir :left)
+(local outputs {:right 1
+                :left 2
+                :up 4
+                :down 8
+                :break 16
+                :rejuv 32
+                :error 64
+                :check 128})
 
 (fn pulse-signal [output]
   (local id (. outputs output))
-
   (redstone.setBundledOutput cable-dir id)
   (os.sleep 1)
   (redstone.setBundledOutput cable-dir 0)
   (os.sleep 1))
 
+(fn check-gantry []
+  (print "Checking gantry position")
+  (redstone.setBundledOutput cable-dir (. outputs :break))
+  (os.sleep 2)
+  (when (not (= (redstone.getBundledInput cable-dir)
+                (+ (. outputs :break) (. outputs :check))))
+    (error "Incorrect gantry position!")))
 
-(print "Moving gantry into chunk")
-(for [_ 1 16]
-  (pulse-signal :right))
+(fn run []
+  (check-gantry)
+  (print "Moving gantry into chunk")
+  (for [_ 1 16]
+    (pulse-signal :right))
+  (print :Mining)
+  (for [_ 1 depth]
+    (pulse-signal :down)
+    (pulse-signal :break))
+  ;; Wait for items to go into chest
+  (print "Waiting for items")
+  (os.sleep 60)
+  (print "Resetting gantry")
+  (for [_ 1 depth]
+    (pulse-signal :up))
+  (for [_ 1 16]
+    (pulse-signal :left))
+  (os.sleep 3)
+  (check-gantry)
+  (print "Activating rejuvenator")
+  (redstone.setBundledOutput cable-dir (. outputs :rejuv))
+  (os.sleep 20)
+  (redstone.setBundledOutput cable-dir 0)
+  nil)
 
-(print "Mining")
-(for [_ 1 depth]
-  (pulse-signal :down)
-  (pulse-signal :break))
-
-;; Wait for items to go into chest
-(print "Waiting for items")
-(os.sleep 60)
-
-(print "Resetting gantry")
-(for [_ 1 depth]
-  (pulse-signal :up))
-
-(for [_ 1 16]
-  (pulse-signal :left))
-
-(os.sleep 3)
-
-(print "Activating rejuvenator")
-(redstone.setBundledOutput cable-dir (. outputs :rejuv))
-(os.sleep 20)
-(redstone.setBundledOutput cable-dir 0)
+(local (_ err) (pcall run []))
+(when err
+  (print err)
+  (redstone.setBundledOutput cable-dir (. outputs :error)))