Double-layer Manhole Cover Monitor

WORKING PRINCIPLE

The terminal is installed on the back of the lower manhole cover (compound manhole cover). The magnet is mounted on the upper manhole cover. When the upper manhole cover is opened, the sensitive magnetic sensor in the monitoring terminal will detect and trigger the alarm. When the lower manhole cover is opened and the inclination value is greater than the set alarm threshold, the alarm is triggered (when the inclination value is bigger than 90°, the unconditional alarm is triggered). The alarm signal is sent to the monitoring center through wireless transmission. In addition, when the monitoring terminal sends alarm information to the management platform, it will trigger the high-decibel buzzer alarm.

The device supports setting the timing reporting interval and alarm angle threshold (default 10°). In the non-alarm State, the terminal sends the notification message at regular time interval. In the alarm state, the terminal will send the message immediately, when the angle is normal, the terminal will also send the message to the platform immediately. The status flag in the message can be used to determine whether it’s the alarm or normal status. When the device detects that the battery voltage is low, the device reports a low voltage warning message. The device sends the timing state report information according to the set timing report time interval.

The conditions of abnormal movement are: |current angle – initial angle|＞ alarm angle threshold.

When the condition is met, an alarm message is sent