InteliSENS® SL mini-WSeries Speed & Length Gauge


InteliSENS® SL mini-WSeries Speed & Length Gauge


  • Non-contact, high-speed, solid-state laser speed and length measurement with no slippage, drift, mechanical wear or maintenance compared with contact wheel / roller systems.
  • Wire optomized SL mini-W series version available for wire and cable applications
  • Unidirectional speed and length measurement.
  • Ultra-compact design with a footprint comparable to a smartphone.
  • Optimized for sheet material and converting applications.
  • UKAS-traceable calibration; accuracy better than 0.05% and repeatability better than 0.02%.
  • Rugged industrial design for use in factory environments.
  • Available fitted with industry-standard communcations interfaces for easy integration with PLCs and production line equipment.
  • Excellent value with low cost of ownership.


Proton Products InteliSENS® SL mini Series non-contact, unidirectional speed and length gauges provide extremely accurate speed and length measurements in almost any sheet material or converting application.

Production processes for web products, woven and non-woven materials, paper, plastic film, tapes, building materials, flooring and labelling can all be measured using the laser Doppler method.

Applications requiring a precise cut-to-length process benefit from the non-slip and highly accurate laser measurement technique which reduces scrap, increases uptime and improves material yield by eliminating product “Give Away” or “Short Length” claims.

InteliSENS® SL mini Series gauges are money-saving, direct replacements for traditional problematic and high-maintenance contact wheel and roller-type devices and are extremely easy to install and operate. Integration with production line controllers such as PLCs is eased by the availability of a wide variety of industry standard communications interfaces.

Operating principle – Laser surface velocimeter

Proton Products InteliSENS® SL mini Series speed and length gauges illuminate the measured surface with an interference pattern created by the intersection of two laser beams. The alternating bright and dark interference fringes modulate the light scattered by the object with a frequency proportional to the object speed. This scattered light is detected by a photodiode and the electrical signal digitally processed to determine the frequency and hence the speed. Object length is then calculated by integrating the speed measurement over time.


Model SL mini 1220 SL mini 3060 Units
Part number 00050MC001 00050MC002
Stand-off distance 120 300 mm
4.72 11.8 inch
Depth-of-field 20 60 mm
0.79 2.36 inch
Minimum speed 0.1 0.25 m/min
0.33 0.82 ft/min
Maximum speed 2000 5000 m/min
6560 16400 ft/min
Specification Minimum Typical Maximum Units
Accuracy* 0.05 %
Repeatability 0.02 %
Acceleration 500 m/s2
Internal measurement rate 200 kHz
Measurement output interval 20 µs
Laser spot diameter 3 mm
Operating temperature 5 40 °C
41 104 °F
Ingress protection IP67
Weight 1.1 kg
2.4 lb
Length 142 mm
5.59 inch
Width 104 mm
4.09 inch
Height 52 mm
2.05 inch
Power supply 15 24 25 VDC
Power consumption 8 W
*only valid if the measured object is positioned within the central 20% of the depth-of-field.
Measurement units
(end-user configurable)
Speed metres/minute feet/minute
Length metres feet yards
Laser safety control inputs Laser External closed contact to ground enables laser diode.
Shutter External closed contact to ground opens laser shutter.
Shutter status output Electrical N-channel MOSFET pull-down (for connection to user-supplied opto-isolated relay).
Maximum voltage: 30VDC Maximum current: 100mA
Function Pulled to ground when laser shutter is open.
3×Logic inputs
(end-user configurable)
Electrical Maximum input voltage: 24VDC
Function Length reset Display hold Length hold
Speed hold Direction Pause
2×Logic outputs
(end-user configurable)
Electrical N-channel MOSFET pull-down (for connection to user-supplied opto-isolated relay).
Maximum voltage: 30VDC Maximum current: 100mA
Function Gauge OK Laser at temp Laser on
Measuring Preset Length 1 Preset Length 2
2×Differential pair pulse outputs
(end-user configurable)
Electrical Opto-isolated differential pair
Output voltage: 5V or user supplied (up to 24V)
Maximum frequency: 1MHz
Function Independent Quadrature pair
CANbus communications Connects to an optional Proton Products CDi interface display unit
Serial communications RS-232
Ethernet communications Modbus protocol
Optional communications (factory-installed, choice of one, replaces standard Ethernet interface) PROFIBUS Ethernet/IP DeviceNET