Magnetic Sensors:- Magnetic proximity sensors are characterized by the possibility of large switching distances, available from sensors with small dimensions. They detect magnetic objects (usually permanent magnets), which are used to trigger the switching process. As the magnetic fields are able to pass through many non-magnetic materials, the switching process can also be triggered without the need for direct exposure to the target object. By using magnetic conductors (e.g., iron), the magnetic field can be transmitted over greater distances so that, for example, the signal can be carried away from high temperature areas.
Proximity sensing is the technique of detecting the presence or absence of an object using a critical distance. A position sensor determines an object's coordinates (linear or angular) with respect to a reference, displacement means moving from one position to another for a specified distance (or angle). In effect, a proximity sensor is a threshold version of a position sensor.
Introduction Series SW-705/ SW 715/ MSP 706/ MSP 716/ MSP 707/ MSP 717:- The series SW 705 Magnetic Proximity Switches are available in two broad categories.
Position sensing switches with Reed Element.
2-Wire/3-Wire Magnetic pick-up Sensors:- These switches are available in different shapes and sizes. Tubular models are available in Brass/SS enclosures in sizes M12, M18 and M30 and above.
Switches with Reed Element:- These switches are used only for position sensing application. These incorporate a hermetically sealed sensitive reed element. The object should necessarily be a magnet. These are provided with 2-core built-in cable. The output is a potential free contact and can switch external load directly.
The switching voltage and contact rating depends upon switch size. Special models of latching type switches are available for direction sensing applications.
10 to 50 mm depending upon Strength of object magnet.
Integrated 2/3-core cable.
500 mA Max.
70°C / 200°C.
Applications:- 1)Position sensing in hydraulic cylinders. 2)Roto-meters. 3) Direction sensing applications.
4)Level sensing of liquids.
Magnetic Pick-Up Sensors:-(Series MSP 706/MSP 716)
Hall Effect Sensors:- (Series MSP 707/MSP 717)
These sensors can be used only for sensing motion of a ferrous object e.g. Gear Wheel. These incorporate a special high strength ALNICO Magnet with a properly designed coil. Special high frequency sensors incorporate a Hall effect sensor.
These switches are available in 2/3-wire design. The 3-wire type switches have output logics / operating voltages similar to other types of switches described earlier.
The 2-wire switches should be necessarily used with a special controller / amplifier unit.
Applications:-1) Turbine high-speed sensor. 2) Bucket Elevator high temperature sensor.
Automobile Sensors:-Special / custom built models are available for Automobile applications as below; Transfer case speed sensor.