Safety Laser Scanner

"The technology behind the laser scanner is a single device that uses diffuse reflectance instead of a safety light curtain, for example, that uses an emitter/receiver and is considered a through-beam type of device," says Mike Carlson, Safety Products Marketing Manager for Banner Engineering. "The laser is used to illuminate an object, and the reflected light is measured to capture the time of light between the scanner and the object."

The laser scanner has two primary applications which both deal with area guarding and detecting an individual within a certain area. One application is mobile vehicles for collision avoidance where the user can control not only starting and stopping, but also speed. Depending on where the field is broken, the system can start slowing down or switch fields.

In a true area guarding application, such as the interior of a robot cell to make sure there are no people within an area, the scanner can provide either a stop signal or prevent a reset of a secondary guard such as a gate interlocking switch. The scanner has two solid state safety outputs and two auxiliary solid state, non-safe outputs.

Simple installation and intuitive configuration software make the AG4 a solution to effectively safeguard irregularly-shaped areas not suitable for a standard two-or three-piece safety light screen, and is also a replacement for safety mats. By meeting all requirements for Type 3 per IEC 61496-1/-2, Category 3 PLd per EN ISO 13849-1 and Safety Integrity Level (SIL) 2 per IEC 61508, the AG4 delivers superior performance in applications including area guarding, access/perimeter guarding and automated guided vehicle (AGV) collision avoidance.

"We saw a need for a solution that could be used as a stand-alone safeguard that would stop hazards when an individual enters an area, as well as to prevent the reinitiating of a machine cycle while that individual is within the guarded area," says Carlson. "The AG4 will provide a solution in any number of stationary applications, but also is an excellent solution for collision avoidance on mobile vehicles such as AGVs, overhead cranes and transfer carts and trolleys."

Using diffuse reflectance (reflected light) to determine an object's position via range (measured distance) and rotational angle, once protective and warning fields are configured, the position of the objects within the field of view are evaluated. If any are within a protective field, a safety stop signal is generated from the scanner. The AG4 can additionally be configured so that an intrusion in the warning field triggers an auxiliary output which may be used to slow a mobile vehicle, flash a light, or initiate other actions to warn an individual who enters this field.

Featuring a 0.36 degree lateral resolution, the AG4 reliably detects objects in a zone up to 190 degrees from its fixed position. It provides selectable protection field resolution of 30, 40, 50, 70 and 150 mm with ranges up to 6.25 m while its warning field provides coverage of up to 15 m. Advanced configuration capabilities allow operators to configure the AG4 with eight individual protective and warning fields. Users can quickly switch between configured field pairs, providing the flexibility to effectively protect personnel and equipment in diverse applications.