The sensitive element of the magnetic sensor can be a Hall effect cell, a magnetoresistance or a reed switch detecting the presence of a magnetic field, generally a permanent magnet. It detects without contact the position of the magnet and transmits an electrical signal.
Polyamide level sensors can be used in low chlorinated water such as swimming pools but polypropylene sensors are more suitable.
When in the application there is a problem of agitation of the level (wave effect) it is necessary to put the detector in an anti wave system. Generally this system consists of a closed tube which envelops the detector and which is pierced with at least 2 holes (it is necessary to think of the evacuation of the air when the level rises).
The smaller the holes, the greater the difference between the real level and the level inside the tube: it is therefore necessary to find the right compromise: eliminating waves and good level monitoring.
The main advantages are:
- No power supply required. No current consumption in open state with real galvanic isolation and no voltage drop in closed state.
- Works in difficult environments: wide temperature range, insensitive to dust, water projections, ...
- The detection distances can be very large. They will depend mainly on the magnetic sensitivity of the bulb and the power of the magnet as well as the magnetic environment of the couple Reed Switch + Magnet.
- Very economical compared to all other technologies.