diff --git a/sequencer/sequencer.sh b/sequencer/sequencer.sh
index 2514513..b407405 100755
--- a/sequencer/sequencer.sh
+++ b/sequencer/sequencer.sh
@@ -7,9 +7,9 @@
 
 ## Version information
 
-VERSION_REV=12
-VERSION_MAJOR=2
-VERSION_MINOR=1
+VERSION_REV=13
+VERSION_MAJOR=0
+VERSION_MINOR=0
 
 ## Start of generic script part
 
@@ -235,6 +235,19 @@ cat <<USAGE_API
         String which is displayed in the error output
 
 USAGE_API
+echo -e "${GREEN} exitIfRunning${NC}"
+cat <<USAGE_API
+    End sequence if an instance of it is still running
+
+USAGE_API
+}
+
+# check if there is another PID other than this one
+exitIfRunning() {
+if pidof -o %PPID -x "${0##*/}">>/dev/null; then
+  echoseq " [E] Sequence already running"
+  exit 1
+fi
 }
 
 # Echo only if not -qq ($QUIET -ne 2)