Inductive Proximity Sensor LMF27


1) Compact volume, Diversified exterior

2) High precision of repeated location

3) Good performance of anti-interference
4) High on-off frequency, Wide voltage range

5) Dust proof, vibration proof, water proof and oil proof

6) With short-circuit protection and inverted connecting protection




Detection distance




















two wire system






SRC Control label silicon









Relay output

Control output





Output voltage dropDC/AC

DC<3V , DC(Two wire system)<3.9V , AC<10V

Consumption current

DC < 15mA, AC < 10mA

Standard detected object

18×18×1(A3 iron)

Repeated precision


DC/AC Response frequency


Working environment temperature


Insulation resistance


Shell material

ABS Resin

Protection grade

IEC standard IP67

Altemative model at home and abroad

Series connection and parallel connection:

Explanation of technical terms:

Detection distance

Move the  detected  object according  to  assigned method,  the  distance  from  the  reference  position (reference plane)to the detecting action(resetting)

Setting distance

Including the effects like temperature and voltage, without error action the distance passed through from the practical detection surface to the objected object.

Standard detected object

Take  as  standard  detected  object  to  detect  the basic  performance.  the  shape,  size  and  material have been determined.

Differential distance

The  absolute  value  of  the  distance  difference between the distance to action and the distance To resetting

Response time

TI:when  the  objected  object  enters  the  action  zone,  the time from proximity sensor being in action state to output appearance.
T2:the    time    from    leaving    action    zone    to    output disappearance.

Response frequency

Work out the tracking output times per second by repeatedly approaching the detected object
Brief detection method sees the above diagram

Main features:

Take high frequency oscillation type proximity sensor(front detector)as representative example to briefly explain general features of proximity switch.




◆  About detected object

When the material of detected object is non magnetic metal, the distance of action should descend. But when the foil material is approximately thicker than a.01mm,the detection distance will be the same as that of magnetic object If the film plating is extremely thin or non-conductive, detection cannot be conducted. The effect of cladding material, take note of the changing of detection distance.

About ambient weather
In order to maintain reliable action and long service life, please avoid the(outdoor)occasion beyond the stipulated ambient temperature. Do not drench it with Water or water-soluble cutting lubricant when it is used with cover, although the proximity sensor is waterproof. Do not used in the occasions with chemical agents, especially strong base acid, nitric acid, hot strong sulfuric acid and so on.

About maintenance and overhaul
In order to keep the proximity sensor to work stably for long time, the following regular examinations should be performed just like general control.
1.  Check the installation position of detected object and proximity sensor if any deviation, loosening or deformation exists.
2.  Check the attached wires and connecting parts if any loosening bad contact or wire breaking off exists
3.  Check if there is any metallic powder accumulation or not
4.  Check if the temperature condition and surrounding environment condition are normal or not

5. Check if the detection distance is normal or not

The size of detected object and detection distance

If the detected object is square metal sheet with constant thickness (t=1mm), detect at detection distance X when change its side length dmm.


When the detected object is bigger than standard detection distance is constant. According to different Machine type, sometimes the features will that mentioned on the left. To through type, the detection object is like cylinder metal bar

The thickness of detected object and detection distance

Detect  at  detection  distance Xmm(front detector)when change the thickness of the assigned standard detected object 1mm.

For more than 1mm thick magnetic metal like iron on the main, the detection distance will not change.

The effects resulted from the Thickness of detected object and cladding material

Because the detection to standard detected object will be effected by its  shape,  size,  material,  and various cladding material, confirm through  detection  distance  Xmm measurement.

The effects resulted from detection distance and cladding material of the metal excluded iron will be different according to different machine type On the main, the machine type which detects all the metals will not be effected by cladding material.

Correct use, installation and cautions:

Mounting screw switch

◆  Do  not  tighten  with  over-torque  when  mounting  the switch. Adopt toothed washer when tightening

Mounting non screw type pillar switch

◆  When  adopt  adjusting  screw,  the  tightening  torque  should  be within 2-4kgf-cm

◆  Protection   against   the   interference   of   non   detected object

◆ When mounting the proximity switch on the metal part,
do refer to the following diagram. Remain a certain space in advance  according  to  the  shown  diagram  so  as  to  prevent the switch from error action

◆ Protection against mutual interference between switches

◆ Mount  according  to  the  size  which  is  bigger  than  that  in  the following  diagram  to  prevent  the  switch  from  error  action  resulted from mutual interference if mount the switches contra-positively or in parallel

◆  Adjustable switch action distance(sensitivity)

◆  The action distance(sensitivity)of proximity switch can be  adjusted  by  the  means  of  trimming  potentiometer. Increase  the  action   distance  and   reduce  sensitivity when  turn  clockwise.  Vice  versa.  Do  not  use  in  the critical state of max. action distance.

◆Guard of switch lead-wire

◆ When  mount  switch,  fix  the  lead-wire  at  a  distance  about  10cm from the switch with wire clip so as to prevent the switch lead-wire from damage from outer force


◆DC switch should adopt insulation transformer and ensure stable voltage mains corrugation.

◆IF any electric power line or dynamic line passes through the surrounding of switch lead-wire, in order to prevent the switch

from damage or error action, cover the metal bushing on the switch lead-wire and ground it to the earth.

◆Set the switch use distance within the rated distance to avoid the effects from temperature and voltage

◆Wiring  while power-on  is strictly  prohibited. Connecting the wires  strictly  according to the wiring  diagram and  output

return elementary diagram.

◆If there are any special requirements to the switch like water proof, oil proof, acid proof, base proof, high temperature proof

or with any other specifications, the users are required to give clear indication when placing an order. We can produce accord

-ing to the requirements of the use.

Application illustration of proximity switch:

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