diff --git a/site_ansto/instrument/pelican/config/beamline/sct_hv.tcl b/site_ansto/instrument/pelican/config/beamline/sct_hv.tcl
index 9f8dd016..2c0f20ad 100644
--- a/site_ansto/instrument/pelican/config/beamline/sct_hv.tcl
+++ b/site_ansto/instrument/pelican/config/beamline/sct_hv.tcl
@@ -47,16 +47,22 @@ proc ::scobj::hv:setting {par} {
 
   set newPara [sct target]
 
-  switch $par {
-    "hv1" {set comm "hv_set hv1 $newPara"}
-    "hv2" {set comm "hv_set hv2 $newPara"}
-    "i1"  {set comm "hv_set i1 $newPara"}
-    "i2"  {set comm "hv_set i2 $newPara"}
-    default {error "ERROR: illegal parameters, try "hv1","hv2","i1" or "i2""}
-  }
+  if{[sct oldStatus] != $newPara} {
+     set oldStatus $newPara
+     switch $par {
+       "hv1" {set comm "hv_set hv1 $newPara"}
+       "hv2" {set comm "hv_set hv2 $newPara"}
+       "i1"  {set comm "hv_set i1 $newPara"}
+       "i2"  {set comm "hv_set i2 $newPara"}
+       default {error "ERROR: illegal parameters, try "hv1","hv2","i1" or "i2""
+                return idle}
+     }
 
-  sct send $comm
-  return checkReply
+     sct send $comm
+     return checkReply
+  } else {
+    return idle
+  }
 }
 
 proc ::scobj::hv::checkReplyFunc {basePath} {
@@ -83,9 +89,12 @@ proc ::scobj::hv::getParaFunc {} {
 proc ::scobj::hv::rdParaStateFunc {basePath} {
   set replyStr [sct result]
   broadcast "Reply from hv_get: $replyStr"
+
   if {[string first "Error" $replyStr] != -1} {
     broadcast "ERROR: cannot get the current parameters setting from the HV device, check again!"
-  } else {
+  } elseif {$replyStr != [sct oldval]} {
+    sct oldval $replyStr
+    broadcast "oldval = [sct oldval]"
     set s1 [string trimright $replyStr "\n"]
     set s2 [split $s1 "=;"]
 
@@ -126,6 +135,7 @@ proc ::scobj::hv::mkHV {argList} {
   MakeSICSObj $pa(NAME) SCT_OBJECT
   sicslist setatt $pa(NAME) klass instrument
   sicslist setatt $pa(NAME) long_name $pa(NAME)
+  hsetprop /sics/$pa(NAME)  status "IDLE"
 
   hfactory /sics/$pa(NAME)/hv1 plain user int
   hfactory /sics/$pa(NAME)/hv2 plain user int
@@ -136,15 +146,18 @@ proc ::scobj::hv::mkHV {argList} {
   #makesctcontroller sct_hv rfamp $pa(IP):$pa(PORT)
   makesctcontroller sct_hv std $pa(IP):$pa(PORT)
 
-  hsetprop /sics/$pa(NAME) read ::scobj::hv::getParaFunc 
-  hsetprop /sics/$pa(NAME) rdParaState ::scobj::hv::rdParaStateFunc /sics/$pa(NAME)
+  hfactory /sics/$pa(NAME)/status plain user text
+  hsetprop /sics/$pa(NAME)/status read ::scobj::hv::getParaFunc 
+  hsetprop /sics/$pa(NAME)/status rdParaState ::scobj::hv::rdParaStateFunc /sics/$pa(NAME)
+  hsetprop /sics/$pa(NAME)/status oldval UNKNOWN
+  hset     /sics/$pa(NAME)/status idle
 
-  hsetprop /sics/$pa(NAME) tuning $pa(TUNING)
+  hsetprop /sics/$pa(NAME)/status tuning $pa(TUNING)
 
   # Initialise properties required for generating the API for GumTree and to save data
   ::scobj::hinitprops $pa(NAME) hv1 i1 hv2 i2 msg
 
-  sct_hv poll /sics/$pa(NAME) $pa(INTERVAL)
+  sct_hv poll /sics/$pa(NAME)/status $pa(INTERVAL)
 
   if {$pa(TUNING)} {
     hfactory /sics/$pa(NAME)/set_hv1 plain user int
@@ -152,19 +165,23 @@ proc ::scobj::hv::mkHV {argList} {
     hfactory /sics/$pa(NAME)/set_i1  plain user int
     hfactory /sics/$pa(NAME)/set_i2  plain user int
 
-    ::scobj::hinitprops $pa(NAME) set_hv1 set_hv2 set_i1 set_i2
+    ::scobj::hinitprops $pa(NAME) status set_hv1 set_hv2 set_i1 set_i2
 
     hsetprop /sics/$pa(NAME)/set_hv1 write ::scobj::hv:setting "hv1"
     hsetprop /sics/$pa(NAME)/set_hv1 checkReply ::scobj::hv::checkReplyFunc /sics/$pa(NAME) 
+    hsetprop /sics/$pa(NAME)/set_hv1 oldStatus UNKNOWN
 
     hsetprop /sics/$pa(NAME)/set_hv2 write ::scobj::hv:setting "hv2"
     hsetprop /sics/$pa(NAME)/set_hv2 checkReply ::scobj::hv::checkReplyFunc /sics/$pa(NAME)    
+    hsetprop /sics/$pa(NAME)/set_hv2 oldStatus UNKNOWN
 
-    hsetprop /sics/$pa(NAME)/set_i1 write ::scobj::hv:setting "i1"
-    hsetprop /sics/$pa(NAME)/set_i1 checkReply ::scobj::hv::checkReplyFunc /sics/$pa(NAME)    
+    hsetprop /sics/$pa(NAME)/set_i1  write ::scobj::hv:setting "i1"
+    hsetprop /sics/$pa(NAME)/set_i1  checkReply ::scobj::hv::checkReplyFunc /sics/$pa(NAME)    
+    hsetprop /sics/$pa(NAME)/set_i1  oldStatus UNKNOWN
 
-    hsetprop /sics/$pa(NAME)/set_i2 write ::scobj::hv:setting "i2"
-    hsetprop /sics/$pa(NAME)/set_i2 checkReply ::scobj::hv::checkReplyFunc /sics/$pa(NAME)    
+    hsetprop /sics/$pa(NAME)/set_i2  write ::scobj::hv:setting "i2"
+    hsetprop /sics/$pa(NAME)/set_i2  checkReply ::scobj::hv::checkReplyFunc /sics/$pa(NAME)    
+    hsetprop /sics/$pa(NAME)/set_i2  oldStatus UNKNOWN
 
     sct_hv write /sics/$pa(NAME)/set_hv1 $pa(INTERVAL)
     sct_hv write /sics/$pa(NAME)/set_hv2 $pa(INTERVAL)