diff --git a/src/ATBAPP/DeviceControllerDiag.cpp b/src/ATBAPP/DeviceControllerDiag.cpp
index be93ab3..94ce4c9 100644
--- a/src/ATBAPP/DeviceControllerDiag.cpp
+++ b/src/ATBAPP/DeviceControllerDiag.cpp
@@ -62,6 +62,7 @@ void DeviceControllerDiag::diagRequest()
         qCritical() << "DeviceControllerDiag::diagRequest() is already running";
         return;
     }
+    this->machineEventSet.clear();
     this->isRequestRunning = true;
     this->diagRequestTimeoutTimer->start();