Alarm processing: The microprocessor continuously samples the infrared and microwave signals, calculates to determine the infrared and microwave events, and the event count is stored in the buffer together with the time of occurrence. Then, scan the buffer to check the combination of events and their timing to see if the alarm conditions corresponding to the currently set sensitivity are met.

Anti-masking process: The microprocessor monitors the low-gain channel to determine whether there is motion very close to the probe. If close-range motion is detected, a 15-second timer is started. During this period, if no alarm occurs, the probe will consider that damage has occurred and issue an occlusion alarm. The occlusion alarm can only be reset by subsequent valid events (both infrared and microwave detected).

Microwave interference processing-automatic adaptation: the microprocessor uses linear synchronous sampling technology to eliminate interference caused by fluorescent lamps. In addition, an adaptive threshold algorithm is also used, which can automatically and continuously adjust the microwave threshold according to the previous sampling data. In order to "automatically adapt" to small continuous disturbance sources, such as: swinging plants, vibrating objects, fans, etc. When there is microwave activity on the site, the threshold will be relaxed to a fixed maximum value; when there is no microwave activity, the threshold will be reduced to a fixed minimum value.

Self-diagnosis diagnosis: Check the defects of the probe by means of PIR transient transition? Microwave monitoring and thermistor range detection. When the PIR and microwave ratio monitoring conditions are established, it will immediately cause the probe to self-check. The errors found by the diagnosis will be displayed through the LED, regardless of whether the LED is enabled.

Microwave monitoring: Continuous monitoring of the microwave channel is by detecting the pulse signal from the mixing diode.

PIR monitoring-front-end transition: The monitoring of the PIR channel is to add an electrical pulse to the amplifier circuit through the pyroelectric element, which makes the PIR channel have a transition and is detected by the microprocessor. This test will be performed at power-on and every hour thereafter.

PIR automatic temperature compensation-thermistor test: PIR channel temperature compensation is carried out continuously. Every time after reading the thermistor value, check to see if it is within a reasonable range. If not, it means the thermistor is short-circuited or open.

Proportional monitoring: The basic principle of the proportional monitoring circuit is to count the events detected by the two technologies of microwave and infrared, and then use the ratio of the two-the detection ratio to determine the working state of the detector (self and surrounding Environment) is normal. Too many microwave events without infrared events are called MicrowaveInformer conditions; on the contrary, too many infrared events without microwave events are called PIRInformer conditions. Under normal circumstances, most of the microwave Informer conditions appear, that is: the microwave activity is detected through the wall or window and the infrared channel is safe. Any Informer condition will cause the probe to self-check. The Informer condition will only be released when the silent channel receives an event or the self-test is completed. However, the Informer condition is not displayed on the LED.