diff --git a/Safety_demo_analysis/Diagrams_onlineview.md b/Safety_demo_analysis/Diagrams_onlineview.md
index 14ec3f7..b5e3aba 100644
--- a/Safety_demo_analysis/Diagrams_onlineview.md
+++ b/Safety_demo_analysis/Diagrams_onlineview.md
@@ -1,6 +1,7 @@
-# Activity Diagram
+# Activity Diagrams
 ## Assumption
-Assuming the HW to be free of faults, only spatial and temporal interference remain as sources for faults in the execution of the Safety signal source and the Safety app.
+Assuming the HW to be free of faults, only spatial and temporal interference remain as sources for faults in the execution of the Safety signal source and the Safety app. 
 ![system](http://www.plantuml.com/plantuml/proxy?cache=no&src=https://raw.githubusercontent.com/Jochen-Kall/wg-automotive/master/Safety_demo_analysis/Safety_demo_analysis.puml)
-
-![system](http://www.plantuml.com/plantuml/proxy?cache=no&src=https://raw.githubusercontent.com/Jochen-Kall/wg-automotive/master/Safety_demo_analysis/Determine_Safety_status.puml)
\ No newline at end of file
+## Variant with external signal source
+Assuming an external signal source, we get the following abstract schematic:
+![system](http://www.plantuml.com/plantuml/proxy?cache=no&src=https://raw.githubusercontent.com/Jochen-Kall/wg-automotive/master/Safety_demo_analysis/Determine_Safety_status.puml)