diff --git a/site_ansto/instrument/bilby/config/chopper/astrium_chopper.sct b/site_ansto/instrument/bilby/config/chopper/astrium_chopper.sct
index 1d96f111..0c9cc615 100644
--- a/site_ansto/instrument/bilby/config/chopper/astrium_chopper.sct
+++ b/site_ansto/instrument/bilby/config/chopper/astrium_chopper.sct
@@ -13,6 +13,7 @@ driver astrium_chopper = {
     var aspeed = { type = float; mutable = true; }
     var rphase = { type = float; }
     var aphase = { type = float; mutable = true; }
+    var frequency = { type = float; mutable = true; }
   }
 
   group disk_2 = {
@@ -26,6 +27,7 @@ driver astrium_chopper = {
     var aspeed = { type = float; mutable = true; }
     var rphase = { type = float; }
     var aphase = { type = float; mutable = true; }
+    var frequency = { type = float; mutable = true; }
   }
 
   group disk_3 = {
@@ -39,6 +41,7 @@ driver astrium_chopper = {
     var aspeed = { type = float; mutable = true; }
     var rphase = { type = float; }
     var aphase = { type = float; mutable = true; }
+    var frequency = { type = float; mutable = true; }
   }
 
   group disk_4 = {
@@ -52,6 +55,7 @@ driver astrium_chopper = {
     var aspeed = { type = float; mutable = true; }
     var rphase = { type = float; }
     var aphase = { type = float; mutable = true; }
+    var frequency = { type = float; mutable = true; }
   }
 
   code fetch_function fetchState = {%%
@@ -87,8 +91,16 @@ driver astrium_chopper = {
             set rhs "[string trim [lindex ${lst} 1]]"
             sct "attr_${lhs}" "${rhs}"
             set base [pathname [sct]]
-            foreach node [list ASPEED RSPEED APHASE RPHASE MASTER] {
-              if { [string equal -nocase "${lhs}" "${node}"] } {
+            switch [string toupper [string trim ${node}]] {
+              "ASPEED" {
+                if [string is double "${rhs}"] {
+                  set freq [expr "${rhs}" / 60.0]
+                  if { "[hval ${base}/frequency]" != "${freq}" } {
+                    hset ${base}/frequency ${freq}
+                  }
+                }
+              }
+              "RSPEED" "APHASE" "RPHASE" "MASTER" {
                 if { "[hval ${base}/${node}]" != "${rhs}" } {
                   hset ${base}/${node} "${rhs}"
                 }
diff --git a/site_ansto/instrument/bilby/config/chopper/astrium_chopper_sct.tcl b/site_ansto/instrument/bilby/config/chopper/astrium_chopper_sct.tcl
index 9e0cf9c3..f77c8380 100644
--- a/site_ansto/instrument/bilby/config/chopper/astrium_chopper_sct.tcl
+++ b/site_ansto/instrument/bilby/config/chopper/astrium_chopper_sct.tcl
@@ -174,8 +174,16 @@ proc ::scobj::astrium_chopper::readState {tc_root} {
             set rhs "[string trim [lindex ${lst} 1]]"
             sct "attr_${lhs}" "${rhs}"
             set base [pathname [sct]]
-            foreach node [list ASPEED RSPEED APHASE RPHASE MASTER] {
-              if { [string equal -nocase "${lhs}" "${node}"] } {
+            switch [string toupper [string trim ${node}]] {
+              "ASPEED" {
+                if [string is double "${rhs}"] {
+                  set freq [expr "${rhs}" / 60.0]
+                  if { "[hval ${base}/frequency]" != "${freq}" } {
+                    hset ${base}/frequency ${freq}
+                  }
+                }
+              }
+              "RSPEED" "APHASE" "RPHASE" "MASTER" {
                 if { "[hval ${base}/${node}]" != "${rhs}" } {
                   hset ${base}/${node} "${rhs}"
                 }
@@ -269,6 +277,17 @@ proc ::scobj::astrium_chopper::mkDriver { sct_controller name ip_address tcp_por
     hsetprop ${scobj_hpath}/disk_1/aspeed type "part"
     hsetprop ${scobj_hpath}/disk_1/aspeed nxalias "${name}_disk_1_aspeed"
 
+    hfactory ${scobj_hpath}/disk_1/frequency plain user float
+    hsetprop ${scobj_hpath}/disk_1/frequency control true
+    hsetprop ${scobj_hpath}/disk_1/frequency data true
+    hsetprop ${scobj_hpath}/disk_1/frequency mutable true
+    hsetprop ${scobj_hpath}/disk_1/frequency nxsave true
+    hsetprop ${scobj_hpath}/disk_1/frequency oldval 0.0
+    hsetprop ${scobj_hpath}/disk_1/frequency klass "parameter"
+    hsetprop ${scobj_hpath}/disk_1/frequency sdsinfo "::nexus::scobj::sdsinfo"
+    hsetprop ${scobj_hpath}/disk_1/frequency type "part"
+    hsetprop ${scobj_hpath}/disk_1/frequency nxalias "${name}_disk_1_frequency"
+
     hfactory ${scobj_hpath}/disk_1/master plain user text
     hsetprop ${scobj_hpath}/disk_1/master control true
     hsetprop ${scobj_hpath}/disk_1/master data true
@@ -349,6 +368,17 @@ proc ::scobj::astrium_chopper::mkDriver { sct_controller name ip_address tcp_por
     hsetprop ${scobj_hpath}/disk_2/aspeed type "part"
     hsetprop ${scobj_hpath}/disk_2/aspeed nxalias "${name}_disk_2_aspeed"
 
+    hfactory ${scobj_hpath}/disk_2/frequency plain user float
+    hsetprop ${scobj_hpath}/disk_2/frequency control true
+    hsetprop ${scobj_hpath}/disk_2/frequency data true
+    hsetprop ${scobj_hpath}/disk_2/frequency mutable true
+    hsetprop ${scobj_hpath}/disk_2/frequency nxsave true
+    hsetprop ${scobj_hpath}/disk_2/frequency oldval 0.0
+    hsetprop ${scobj_hpath}/disk_2/frequency klass "parameter"
+    hsetprop ${scobj_hpath}/disk_2/frequency sdsinfo "::nexus::scobj::sdsinfo"
+    hsetprop ${scobj_hpath}/disk_2/frequency type "part"
+    hsetprop ${scobj_hpath}/disk_2/frequency nxalias "${name}_disk_2_frequency"
+
     hfactory ${scobj_hpath}/disk_2/master plain user text
     hsetprop ${scobj_hpath}/disk_2/master control true
     hsetprop ${scobj_hpath}/disk_2/master data true
@@ -429,6 +459,17 @@ proc ::scobj::astrium_chopper::mkDriver { sct_controller name ip_address tcp_por
     hsetprop ${scobj_hpath}/disk_3/aspeed type "part"
     hsetprop ${scobj_hpath}/disk_3/aspeed nxalias "${name}_disk_3_aspeed"
 
+    hfactory ${scobj_hpath}/disk_3/frequency plain user float
+    hsetprop ${scobj_hpath}/disk_3/frequency control true
+    hsetprop ${scobj_hpath}/disk_3/frequency data true
+    hsetprop ${scobj_hpath}/disk_3/frequency mutable true
+    hsetprop ${scobj_hpath}/disk_3/frequency nxsave true
+    hsetprop ${scobj_hpath}/disk_3/frequency oldval 0.0
+    hsetprop ${scobj_hpath}/disk_3/frequency klass "parameter"
+    hsetprop ${scobj_hpath}/disk_3/frequency sdsinfo "::nexus::scobj::sdsinfo"
+    hsetprop ${scobj_hpath}/disk_3/frequency type "part"
+    hsetprop ${scobj_hpath}/disk_3/frequency nxalias "${name}_disk_3_frequency"
+
     hfactory ${scobj_hpath}/disk_3/master plain user text
     hsetprop ${scobj_hpath}/disk_3/master control true
     hsetprop ${scobj_hpath}/disk_3/master data true
@@ -509,6 +550,17 @@ proc ::scobj::astrium_chopper::mkDriver { sct_controller name ip_address tcp_por
     hsetprop ${scobj_hpath}/disk_4/aspeed type "part"
     hsetprop ${scobj_hpath}/disk_4/aspeed nxalias "${name}_disk_4_aspeed"
 
+    hfactory ${scobj_hpath}/disk_4/frequency plain user float
+    hsetprop ${scobj_hpath}/disk_4/frequency control true
+    hsetprop ${scobj_hpath}/disk_4/frequency data true
+    hsetprop ${scobj_hpath}/disk_4/frequency mutable true
+    hsetprop ${scobj_hpath}/disk_4/frequency nxsave true
+    hsetprop ${scobj_hpath}/disk_4/frequency oldval 0.0
+    hsetprop ${scobj_hpath}/disk_4/frequency klass "parameter"
+    hsetprop ${scobj_hpath}/disk_4/frequency sdsinfo "::nexus::scobj::sdsinfo"
+    hsetprop ${scobj_hpath}/disk_4/frequency type "part"
+    hsetprop ${scobj_hpath}/disk_4/frequency nxalias "${name}_disk_4_frequency"
+
     hfactory ${scobj_hpath}/disk_4/master plain user text
     hsetprop ${scobj_hpath}/disk_4/master control true
     hsetprop ${scobj_hpath}/disk_4/master data true