Coal thermal power plant of a detection alarm system before running the belt is really ringing the device, which can effectively prevent the alarm failure due to the unpredictability of the occurrence of personal injury, filling a major gap in safety. A feature of the device is no need for separate cabling and can be widely used in existing thermal power plant equipment modification, and alarm products can also be combined to produce a "a feedback alarm", and enhance product competitiveness, market prospects ; If a standard power system, the prospects better.