diff --git a/site_ansto/instrument/config/anticollider/anticollider_common.tcl b/site_ansto/instrument/config/anticollider/anticollider_common.tcl
index 209a3522..011ad101 100644
--- a/site_ansto/instrument/config/anticollider/anticollider_common.tcl
+++ b/site_ansto/instrument/config/anticollider/anticollider_common.tcl
@@ -93,6 +93,7 @@ proc ::anticollider::genveto {veto_rules} {
         lappend condlist $mot $range
       }
       lappend veto_region($vp(for)) [list $vp(forbid) @and $condlist]
+      unset condlist
     } elseif [info exists vp(when)] {
       lappend veto_region($vp(for)) [list $vp(forbid) $vp(when) $vp(in)]
     } else {
@@ -132,12 +133,12 @@ proc ::anticollider::veto_region_acscript {args} {
       foreach row  $veto_region($regmot) {
       if { [lindex $row 1] == "@and"} {
         set forbid [lindex $row 0]
-        set veto 0
+        set veto 1
         foreach {mot range} [lindex $row 2] {
           set pos [SplitReply [$mot]]
           foreach {lower upper} [join $range] {
-            if {$pos >= $lower && $pos <= $upper} {
-              set veto 1
+            if {$pos < $lower || $pos > $upper} {
+              set veto 0
               break
             }
           }
@@ -147,7 +148,10 @@ proc ::anticollider::veto_region_acscript {args} {
         } else {
           foreach {min max} $forbid {}
           if {$min <= $target && $target <= $max} {
-            error "ERROR:The range ($forbid) is forbidden for $regmot when [lindex $row 2]"
+            foreach {mot range} [lindex $row 2] {
+              lappend msg [list $mot in $range]
+            }
+            error "ERROR:The range ($forbid) is forbidden for $regmot when [join $msg { and }]"
           }
         }
       } else {
@@ -212,15 +216,13 @@ proc ::anticollider::init {} {
 lappend ::anticollider::scripts ::anticollider::veto_region_acscript
 proc ::anticollider::acscript {args} {
   set catch_status [ catch {
-    if {[::anticollider::enable $args] == "false"} {
-      return
-    } else {
-      foreach {regmot target} $args {
-        anticollision add 0 $regmot $target
-      }
+    foreach {regmot target} $args {
+      anticollision add 0 $regmot $target
     }
-    foreach script $::anticollider::scripts {
-      $script {*}$args
+    if {[::anticollider::enable $args] == "true"} {
+      foreach script $::anticollider::scripts {
+        $script {*}$args
+      }
     }
   } message ]
   handle_acscript_exception $catch_status $message