NFM Inc,2531 S. Main St.,Los Angeles,CA 90007,USA / Tel:(213)-763-0606 / FAX:(310) 802-3917 / www.nfminc.com

Overview of M5 Point Sensors

The optical distance sensors M5 are used in the field of non-contact measuring technology. They measure the distance of objects according to the principle of triangulation. The M5 distance sensors are manufactured for a wide range of specifications. For each application the suitable sensor is available. The sensors are differentiated by measurement range, light spot diameter and light sources.

Over 9 measuring ranges, from 0.5mm to 400mm are available.

The light spot diameters vary from 0.1mm to 10mm depending of the light source/measuring range.

There are two different light sources. One is a LASER used in the M5/LASER sensor, the other is a LED, used in the M5/LED sensor. Both types have specific advantages for a specific field of application.

Protection cases against scratches, or high temperature are available also.

M5 is much more compact and less expensive than most other optical distance measuring sensors using the triangulation principle.

Please refer to the "Technical Specifications" -on bottom of this page- for more details.

PRINCIPLE OF OPERATION

The sensor's laser beam is converged and directed onto a target . The diffusely reflected light beam from the target is converged again through a lens and projected onto a Position Sensitive Device (PSD). The PSD generates a position-proportional electrical current (see  Figure 1  ). This signal is linearized, taking into consideration various factors of surface reflection and delivering an output voltage proportional to the measured distance. The sensor transmits pulsed light, so the signal is not effected by the ambient light.

The intensity of the light is adjusted automatically, according to the reflection factor of the surface. If eventually the intensity of the reflected light is too low, an alarm output "not enough light" is activated. Shiny surfaces, which reflect the transmitted light directly into the PSD, will lead to another alarm, "too much light" . Both alarms are displayed by separate LED's and are available as logical output signals.

FIGURE 1

TYPICAL APPLICATIONS

· Dimensional testing
· Position recognition of small parts
· Position recognition of parts on a conveyor belt
· Indication that the die is clear on presses
· Detection of material overlap
· Checking tool fracture
· Checking tool positioning
· Robot-arm position detection
· Presence/absence detection of small parts
· Object location through small gaps
· Checking the depth of holes
· Level monitoring

OPTIONS
· Double sensors for ultra precise measurements
· RS 232 interface
 

ACCESSORIES
· Digital display unit
· Case for protection against heat or dust
 

SOFTWARE
· PC based program to monitor accuracy of dimensions in automated production lines with self-learn capability
· PC based program for object recognition of moving parts
 

ADVANTAGES OF M5 / LED SENSORS:
· Higher measuring accuracy at black objects
· No human eyesight safety considerations at all
· Larger light spot enables high integration of scattered surfaces
· Examination of scratches on surfaces
· Lower cost
 

ADVANTAGES OF M5 / LASER SENSORS:
· Shorter response time, 40 µsec rising time for the M25
· Smaller light spot to register fine differences in object's structure
· Better accuracy with striped objects (light / dark transition within the spot)
· No ambiguous result due to shiny objects on the side of the light beam
 

FEATURES:
· Measurement ranges from 0.5 - 400 mm
· Measurement range over 400 mm upon request
· Measuring frequency 10 kHz, 25 kHz or 500 kHz (internal sampling frequency 40, 125 and 500kHz)
· Analog output ± 10 VDC ( ± 5 VDC or 4...20 mA optional)
· Resolution / repeatability < 0.1 µm
· Independent of surface texture and color differences
· Focused light spot, diameter down to 50 µm
· Threshold values for too far / OK / too close adjustable
· Self-test outputs for "not enough" / "too much" light
· Works with most materials such as metal, plastics, ceramics, rubber and paper. Minimum diffuse reflection of 10% required to perform correctly.
· Objects with light / dark stripes can be measured.
· Automatic adjustment of emitted light to the reflective properties of the materials, even for black surfaces.
· Very little influence on the signal up to 5000 Lux. No influence on the signal due to ambient light up to 20000 Lux
· Thickness measurement (using two sensors) even for transparent materials.
· Response time is approx. 100 µsec for the M5L, only 40 µsec for the M25L and 1 msec for M5/ LED (-3db).
· User selectable integration time to reduce noise level and increase measurement accuracy.
· Visual indication of "not enough light" or "too much light".
· Laser diode can be turned off while not in use.
· Capability to synchronize two closely mounted sensors and for thickness measurement of transparent materials to avoid the cross-influence.
· Higher accuracy of better than 5 µm are possible by using two sensors.
· Faster sensors for vibration measurement are available.
· Sensors available with exchangeable protective plastic window for contaminating environment.
· Can be mounted at an angle of ± 30° in axis parallel to the length of the sensor and an angle of ± 15° in axis parallel to the width of the sensor.
· Adjustable switching level
· Linear output voltage proportional to the measured distance.  

TECHNICAL SPECIFICATIONS

M5 LED Sensors · larger dot size (integrates better over rough area)

M5 LASER 10kHz Sensors · ranges from 0.5 to 400mm

M5 LASER 25kHz Sensors · ranges from 0.5 to 200mm

M5 LASER Double Sensors · very precise, ranges from 0.5 to 4mm

M5 LASER Special Sensors · larger reference distances, operation up to 500kHz

under construction