Index: sources/canbus/MessageDispatcher.cpp
===================================================================
diff -u -rebc82b5efe26c1081606fab06a1c99bb4f9c0098 -r6391ea8474352ce1b89d79d3a5eddbf195eab385
--- sources/canbus/MessageDispatcher.cpp	(.../MessageDispatcher.cpp)	(revision ebc82b5efe26c1081606fab06a1c99bb4f9c0098)
+++ sources/canbus/MessageDispatcher.cpp	(.../MessageDispatcher.cpp)	(revision 6391ea8474352ce1b89d79d3a5eddbf195eab385)
@@ -336,7 +336,8 @@
 void MessageDispatcher::onAdjustment(const AdjustHDAlarmVolumeRequestData &vData)
 {
     QVariantList mData;
-    mData += vData.volume / 20; // HD vol range is [1-5] and we show [20%-100%] to user.
+    const int hw2ui =   20; // HD vol range is [1-5] and we show [20%-100%] to user (100 / 5).
+    mData += vData.volume / hw2ui;
     onActionTransmit(GuiActionType::ID_AlarmVolumeSetReq, mData);
 }