--- a/svghmi/svghmi.js	Mon Aug 03 16:30:16 2020 +0200
+++ b/svghmi/svghmi.js	Mon Aug 03 16:32:23 2020 +0200
@@ -191,7 +191,7 @@
     frequency: 1,
     indexes: [heartbeat_index],
     dispatch: function(value) {
-        change_hmi_value(heartbeat_index, "+1");
+        apply_hmi_value(heartbeat_index, value+1);
     }
 });