Safety camera system undercuts light curtains
Sick has developed a camera-based safety system for protecting access to hazardous machinery which, it claims, is cheaper than conventional light curtains, quicker to install, and easier to set up. Sick also claims that the V300 WS system (shown below) is first of its type to offer Cat 3 / SIL 2 protection.
The compact device, which contains both the sensor and a light source, is designed to protect a rectangular area of up to 1m by 1m. It is fitted into one corner of the opening (as shown below), from which it views a reflective tape attached to the two opposite edges. The camera, which has a 110-degree field of view, monitors the area with a resolution of 20mm and avoids any dead zones or blind spots. If any object passes through the protected plane, the system stops the machine within 20ms.
To protect larger areas, or two sides of a machine at right-angles to each other, a pair of the safety cameras can be linked together via a synchronisation input. This allows access to a machine to be protected on two sides, with no need for a corner support member.
The camera, which fits into the grooves in an aluminium profile, monitors the reflective strips continuously for dirt, holes or objects placed over the strip. Any problems are indicated using a set of four LEDs that monitor different segments of the field of view. If necessary, a reflector strip can be replaced rapidly and the device reset using a "push to teach" function.
The camera interface is similar to that of a light curtain so no changes are needed to the control system when upgrading from one form of protection to the other.
A version for Cat 2 / SIL 1 applications, called the V200, is due to be launched soon.
