Strip edge and centre positioning device EVK/EVM

The EVK edge sensor positioning device and the EVM centre sensor positioning device are used for the non-contact strip edge and strip centre sensing of steel strip. The device, which is highly reliable and unsusceptible to external interference, visually detects changes in the edge and/or centre position of the strip.

The strip edge is detected via a motorised, mobile sensor positioning device that is equipped with high-frequency (HF) alternating light measuring receivers LS 13/14 , which are protected against ambient light. If the strip edge is displaced due to a change in strip width or a lateral strip deviation, this is detected by the photocells.

The superordinate control electronics then activates the DC motor to move the LS 13/14  and the actuator (servo valve  or electric servo cylinder ) of the control circuit in order to ensure that the strip edge always covers half of the measuring range of the photocell.

Contamination of the light emitters is compensated by applying the reference measuring principle. This involves each measuring system using a measuring receiver and a reference receiver directed to the same light spot of the light emitter. While the measuring photocell detects the lateral position of the strip edge the reference photocell measures the background brightness of the light spot.

Customer benefits:

  • Precise and reliable measuring accuracy, as the system is insensitive to fluctuations in strip height
  • Distance between sensor and light source up to 4 m
  • High reliability and easy operation
  • Short commissioning time thanks to quick and simple installation (minimal installation space)
  • Active dirt compensation thanks to reference measurement principle
  • Also suitable for use in harsh environments (e.g. pickling lines, cold-rolling mills, etc.)
  • Protected against ambient light through the use of HF alternating light

The following components belong to the optical strip edge and centre guiding systems:

  • LLS Linear Light Emitter
  • Alternating light measuring receivers LS

For further information regarding the areas of application and technical data, please refer to our product brochure.

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