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IR safety camera offers an alternative to light curtains
Published:  02 July, 2015

Sick has developed an infra-red (IR) camera that, it says, offers a convenient and reliable Type 3 alternative to safety guard light curtains in production and warehouse environments. The PL d compliant V300 camera has a 20mm resolution and can protect areas up to 1.5 x 1.5m – or larger, if several of the cameras are synchronised.

“The V300 is an incredibly useful device,” says Dr Martin Kidman, Sick’s machinery safety specialist in the UK. “It also solves the problem where a Type 2 light curtain now no longer meets the requirements for PL d applications, and the change to a Type 4 light curtain is too expensive, or is clumsy and intrusive.”

The safety camera is an IR-based scanner that detects light bounced back from a strip of reflective tape that defines the protected field. Its 110-degree field of view allows full coverage of openings up to 1.5 x 1.5m, with a field depth of about 10 degrees on either side for additional coverage. This allows optimal positioning, while offering protection without blind spots.

The flexible, self-adhesive reflective strips can be contoured to allow for discontinuities such as steps, cable runs or housings, or even curves and round shapes such as rotary table housings. Unlike light curtains, the protected field does not need to be rectilinear, allowing new designs for safety guarding.

In tests, the reflective strips have survived a loaded crate being pushed over them 10,000 times. Their strong adhesive will not detach even under severe industrial conditions, and the camera is smart enough to ignore scratches in the strip while detecting human body parts inserted into the field.

Sick's V300 camera (shown in yellow) monitors reflected infra-red beams to protect against unauthorised access

A right-angled mount allows the camera to be fitted unobtrusively in the top corner of a portal or other entrance to a guarded area, or integrated into the steelwork frame. It does not restrict access and is not as vulnerable to accidental damage as a light curtain.

The 20mm resolution is sufficient to detect human intrusion to hand size, and the 20ms response time is fast enough to allow machinery to be stopped safely. Once the camera is positioned opposite the reflective tape, one press of a teach-in button sets it up.