Inductive Proximity Switches

Inductive proximity switches are ideally suitable for no contact sensing of metallic objects. As inductive sensors work on electromagnetic principle, they are inherently resistant to dust, humidity and oil in industrial environment. Besides Proximity detection, continuous development in the field has led to new applications such as distance measurement with Analogue Types. Low power consumption ,availability in wide range of packages and low unit price has made them very popular in industry.

Standard Barrel Types

Housings of standard inductive ranges are made of Nickel coated brass barrels. They are widely used in non-corrosive atmospheres.

Limit Switch Style Blocks.

With housings moulded in engineering plastic material these switches replace mechanical limit switches. KATLAX offers Models with multiaxes sensing to adopt design flexibility.

Flat Types

These models in engineering plastic are best fit for conveyor belt applications to overcome z-axis limitations. They virtually substitute mechanical micro switches.

Slotted Types

Designed for RPM measurement and zero speed detection these slotted versions are also available in engineering plastic housings.

Design And Principle

KATLAX Inductive Sensors are no contact type electronic sensors comprising of three components oscillator, comparator and output stage. Catalogue specifies sensing distance for Fe ST-37 grade steel plate and necessary Correction Factor must be considered for different metals. ( refer table 1 ).

Operation

The oscillator creates high frequency electromagnetic field which radiates from sensing face of the sensor. When damped with metallic object, eddy currents are induced in metal causing change in amplitude of oscillations. This signal is conditioned to change Schmitt trigger output and state of output amplifier. Analogue DC output voltage and current are available in addition to standard PNP/NPN switching outputs.

Definitions

Sensing distance(Sn)

Distance at which output signal is triggered when standard target is moved towards sensing face.

Standard target

Square plate st-37 /Fe length of the side equal to sensing face diameter.

Correction factor(C.F.)

If target differs from standard test target, then the applicable published sensing distance must be multiplied by appropriate correction factor.

MATERIAL	C.F.
Mild Steel	1.00
Stainless Steel	0.70
Brass	0.45
Aluminum	0.35
Copper	0.25

Hysteresis(H)

Difference in distance between operate and release points given in terms of percentage of sensing distance. KATLAX switches are designed for 3% to 15% over its range of operating conditions.

Repeatability(R)

The repeatability of actual switching point of two successive switching within 8 hours.

Temperature

The normal temperature range between 0 to 70 Deg.C.

Switching Frequency (F)

Highest frequency at which proximity sensor can be switched.

Mounting Instructions

For Cylindrical Forms

Shielded
Sensor can be mounted flush in the metal.

Unshielded

There must be space equal to diameter of sensing head with no metal interference.

For Limit Switch Styles

40 Block type switches : Mounting should be done as shown.

Electrical and Mechanical Specifications

Supply Voltage(Vb)

Maximum ripple of 10% of supply voltage should not be exceeded.

Voltage Drop(Vd)

Maximum voltage drop measured across conducting output.

Current Consumption(Ia)

Maximum current drawn by switch.

Output Load Current(IL)

Maximum current switch can sink or source should not be exceeded.

Output Protection

KATLAX switches are protected against
BACK EMF,
REVERSE POLARITY,
& INDEFINITE OUTPUT SHORT- CIRCUIT.

Magnetic Fields

Strong Magnetic Fields may push proximity switch into latching condition. e.g. Induction Furnaces. Protective screening is recommended in such cases.

Cable Length

KATLAX standard proximity switches are furnished with 3m Cable. Longer lengths add capacitive coupling on output leading to switching limitations and /or noise problems.

Status

KATLAX switches are provided with LED indication.

Protection Class

KATLAX Proximity Switches are approved for IP67 class of protection against ingress of water at specified pressure and time conditions

Electrical Configurations

Namur Sensors

These low current two wire sensors developed at KATLAX are approved by CMRI., Dhanbad for INTRINSICALLY SAFE AREA APPLICATIONS as per IS 5780-1980 and can be operated in Ex-PROOF areas Gr I,IIA,IIB,IIIC .

DC/AC Switching Sensors

These high output current driving capacity sensors are manufactured to operate over wide range of supply conditions 10 to 30 Vdc / 40 to 250Vac.

Analogue Sensors

These are available in standard process control protocol viz. 4-20 mA. /0-10V output proportional to target distance.

Metallic or Plastic with Cylindrical, Flat, Slot or Customized Mounting, Certified for IP 67, Short Circuit, Overload, Polarity reversal Protection.

Reflex, Retro-reflective, Through Beam, Colour Mark.