merge with filling value for files

apps/timeseries/output.py

@@ -228,11 +228,12 @@ def get_output(params):
                 return error_nodata(params, Error.RESPONSE)
 
         st = get_processed_signal(st, params)
-        st.merge(method=1)
 
         if params["format"] == "plot":
+            st.merge(method=1)
             response = static_plots(params, st)
         else:
+            st.merge(method=1, fill_value=0)
             response = get_file(params, st)
         return response
     except (MemoryError, ValueError) as plotex: