diff --git a/LSL2/STPROC/RDS_EVENTS.txt b/LSL2/STPROC/RDS_EVENTS.txt
index cfbd741..4872cc7 100644
--- a/LSL2/STPROC/RDS_EVENTS.txt
+++ b/LSL2/STPROC/RDS_EVENTS.txt
@@ -349,20 +349,31 @@ Event PUB_SIGN.CLICK()
 						Response    = Dialog_Box('NDW_VERIFY_USER', @WINDOW, initParams)
 						Valid       = Response<1>
 						If (Valid EQ True$) then
+						    debug
 						    if XLATE('APP_INFO', 'NEW_TW_SYSTEM_ACTIVE_SWITCH', 1, 'X') EQ True$ then
                                 UsingTestWafers = Msg(@Window, '', 'YESNO', '', 'Log Test Wafer Usage':@FM:'Are any test wafers loaded?')
+                                IsTWReqd        = RDS_Services('IsTWLoggingReqd', RDSNo)
                                 If UsingTestWafers then
                                    TWLogResult = Dialog_Box('NDW_LOG_TEST_WAFER_USAGE', @Window, RDSNo : @VM : 'STANDARD' : @VM : 'REACTOR' : @VM :  Reactor)
                                    If TWLogResult then
                                        QA_Services('SignLoadStage', RDSNo, @USER4, WfrQty, LLSide)
                                    end else
-                                       ContinueLoad = Msg(@Window, '', 'YESNO', '', 'Continue?':@FM:'Test wafer logging was cancelled. Do you wish to continue signing?')
-                                       If ContinueLoad then
-                                           QA_Services('SignLoadStage', RDSNo, @USER4, WfrQty, LLSide)
+                                       If IsTWReqd then
+                                           Msg(@Window, 'Unable to sign load because test wafer logging is required on this run.')
+                                       end else
+                                           ContinueLoad = Msg(@Window, '', 'YESNO', '', 'Continue?':@FM:'Test wafer logging was cancelled. Do you wish to continue signing?')
+                                           If ContinueLoad then
+                                               QA_Services('SignLoadStage', RDSNo, @USER4, WfrQty, LLSide)
+                                           end
                                        end
                                    end
                                 end else
-                                    QA_Services('SignLoadStage', RDSNo, @USER4, WfrQty, LLSide)
+                                    if IsTWReqd EQ False$ then
+                                        QA_Services('SignLoadStage', RDSNo, @USER4, WfrQty, LLSide)
+                                    end else
+                                        Msg(@Window, 'Unable to sign load because test wafer logging is required on this run.')
+                                    end
+                                    
                                 end    
 						    end else
 						        QA_Services('SignLoadStage', RDSNo, @USER4, WfrQty, LLSide)
@@ -704,3 +715,4 @@ return
 
 
 
+
diff --git a/LSL2/STPROC/RDS_SERVICES.txt b/LSL2/STPROC/RDS_SERVICES.txt
index cb20547..2f8e4c1 100644
--- a/LSL2/STPROC/RDS_SERVICES.txt
+++ b/LSL2/STPROC/RDS_SERVICES.txt
@@ -117,7 +117,7 @@ Declare function    Work_Order_Services, SRP_JSON, Logging_Services, Environment
 Declare function    Memberof, Obj_WO_Mat, Obj_WO_Mat_Log, SRP_Array, DateTime, Dialog_Box, obj_Prod_Spec
 Declare function    RDS_Services, RTI_DistinctList, GetTickCount, Clean_Insp_Services, WO_Mat_QA_Services
 Declare function    PSN_Services, Rds_Layer_Services, SRP_Rotate_Array, Qa_Services, SRP_Date, SRP_Time, SRP_Datetime
-Declare function	Reactor_Services, Signature_Services
+Declare function	Reactor_Services, Signature_Services, obj_rds, Test_Run_Services
 
 LogPath       = Environment_Services('GetApplicationRootPath') : '\LogFiles\RDS'
 LogDate       = Oconv(Date(), 'D4/')
@@ -415,7 +415,6 @@ end service
 // Rows are @FM delimted while columns are @VM delimited.
 //----------------------------------------------------------------------------------------------------------------------
 Service GetRDSData(WorkOrderNo, Columns, ShowGasGauge, RDSOverrideList)
-	
 	RDSList   = ''
 	
 	If ( (WorkOrderNo NE '') or (RDSOverrideList NE '') ) then
@@ -742,6 +741,23 @@ Service IsValidSubLot(RDSNo, RDSType, SupplierLot)
 	Response = IsValid
 end service
 
+Service IsTWLoggingReqd(RDSNo)
+    Response   = False$
+    RDSRec     = Database_Services('ReadDataRow', 'RDS', RDSNo, True$, 0, False$)
+    IsHGCVReqd = obj_RDS('MetPropFlag', RDSNo:@RM:RDSRec:@RM:'CRES')
+    If IsHGCVReqd NE True$ then
+        ExistingTWKeys = Test_Run_Services('GetTestRunKeysByRDS', RDSNo)
+        If ExistingTWKeys EQ '' then
+            Response = True$
+        end else
+            Response = False$
+        end
+        
+    end else
+        Response = True$
+    end
+end service
+
 //----------------------------------------------------------------------------------------------------------------------
 // VerifyEPPMetrology
 //
@@ -1638,3 +1654,4 @@ ClearCursors:
 	
 return
 
+
diff --git a/LSL2/STPROC/TEST_RUN_SERVICES.txt b/LSL2/STPROC/TEST_RUN_SERVICES.txt
index 7d5e3c7..61a942e 100644
--- a/LSL2/STPROC/TEST_RUN_SERVICES.txt
+++ b/LSL2/STPROC/TEST_RUN_SERVICES.txt
@@ -684,7 +684,18 @@ Service GetTestRunKeysByPSN(PSNo)
 end service
 
 Service GetTestRunKeysByRDS(RDSNo)
-    
+    table = "TEST_RUN"
+    Open "DICT ":table To @DICT Else
+        Error_Services('Add', 'Error opening TEST_RUN dictionary')
+    End
+    If Error_Services('NoError') then
+        srch_strng = "RDS_ID":@VM:RDSNo:@FM
+        keylist         = ""
+        option          = ""
+        flag            = ""
+        Btree.Extract(srch_strng, table, @DICT, keylist, option, flag)
+        Response = keylist
+    end
 end service
 
 Service GetTestRunWaferByID(TRWaferID)
@@ -747,3 +758,4 @@ end service
 
 
 
+