The XDG3253Y speed impact sub monitoring device is suitable for key equipment to address pain points that are invisible and difficult to measure in the emergency governor of the steam turbine. The intelligent speed impact sub monitoring device provides an effective technical means. This device is not only a high-precision tachometer, but also specifically designed to monitor the motion status of the impactor. It automatically records the rotational speed during the "striking" and "retracting" moments of the impactor, and stores it internally. At the same time, it can also record the highest rotational speed of the unit, and the data can be easily queried through the panel.