diff --git a/tsg_util/updateTsgStruct.m b/tsg_util/updateTsgStruct.m
index 37dc4eee1e7033a0cc098c1b4b13a6b17d03a4ec..9ace0f1d865e3f2d84ef38fc63d1655407cfb8dd 100644
--- a/tsg_util/updateTsgStruct.m
+++ b/tsg_util/updateTsgStruct.m
@@ -107,10 +107,22 @@ var ={'SSJT_LINCOEF', 'CNDC_LINCOEF', 'SSTP_LINCOEF'};
 lin_type = {'offset','slope'};
 lin_val  = [0,1];
 
+% loop over each variables
+% ------------------------
 for i = 1:numel(var)
+  
+  % check if var_LINCOEF not empty
+  % -----------------------------------  
   if isempty(tsg.(var{i}))
     for j = 1:tsg.dim.LINCOEF
       tsg.(var{i})(j) = lin_val(j);
+    end
+  end
+  
+  % check if var_LINCOEF_CONV not empty
+  % -----------------------------------
+  if isempty(tsg.([var{i} '_CONV']))
+    for j = 1:tsg.dim.LINCOEF
       tsg.([var{i} '_CONV']) = ...
         [tsg.([var{i} '_CONV']); padding(lin_type{j}, tsg.dim.COEF_CONV_SIZE)];
     end