Safety Laser Scanners

A safety laser scanner is based on the time-of-flight pulse measurement with a rotating mirror scanner head. The scanner array sends out pulsed infrared laser light (not detectable to the naked eye, Safe Class 1) and measures the one-way travel time of each returning pulse to derive the external object distance information. The scanner software then compares detected object positions with previous preset parameter zones for warning zones (visual beeps, lights, machine sound alarms) and green-yellow or red safety zones (Shutdown the motion) in response.

Functionally, our laser scanner is required to be compliant to IEC 61496-3 (Type 3 electrosensitive protective equipment), IEC 61508 (SIL 2 safety response level), and ISO 13849-1 (PLd, Category 3 performance level). Type 3 desigh is the level at which the device stops the motion when objects are detected based on diffuse reflection laser light. SIL 2 means dangerous failure rate is below 10^-2. PLd Category 3 means Single Fail-Net Reliability is a component requirement. European facilities must be CE-marked for directive 2006/42/EC, American offices are governed by OSHA 29 CFR 1910.212.

Yes, in many scenarios. Safety laser scanners can offer safety equivalent or better performance with more flexibility as the laser scanner detects your pre-defined 2D volume from a single mounting point and a light curtain just to cover one plane of area between two columns. They work better for applications with irregular shape of zones, non-fixed mounted volume (AGV/AMR) or changing layouts. Inversely, light curtains tend to be preferable for narrow access guarding points in clean areas in food, beverage, and packaging applications where type 4 (highest safety category) is needed – light curtains can be type 4 though laser scanners can only be type 3. The best approach for each application varies on your risk assessment and the area coverage you need to detect.

Three parameters to determine selection: 1) protection field length: (has to be at least as high as the stopping distance of your vehicle at maximum vehicle speed), 2) configurable field sets: (how many different zone configurations can the scanner remember, for different vehicle operation conditions),3) protocol (CIP Safety for AB controllers, PROFIsafe for Siemens).AGV’s mostly require bank switching capability to change the active protection zone depending on vehicle speed, direction of travel and load condition. It is important to check the parameters of the scanner height-agp is only 80mm, which fits under a standard Euro pallet.

Most frequent sources of unnecessary safety stops on nuisance safety stops are dust in the air, interference from ambient light (direct sunlight as well as high-bay lighting) and small objects at the boundary of the monitored zone. Better safety laser scanners provide configurable multi-sampling (where the receiver takes several consecutive samples before generating a detection signal), color/ambient-light filtering and selectable minimumm detectable object size. Our QS-series employs sophisticated signal processing algorithms that separate ephemeral sources of ambient noise from valid intrusions, helping to achieve false trip rates that many users of older scanner generations have cited as nuisance in various online forums.

CIP Safety is supported on the Compact Safety Laser Scanner and Safety Area Scanner models for direct integration with Rockwell Automation GuardLogix and CompactGuardLogix safety controllers over EtherNet/IP. PROFIsafe is supported on the Safety Area Scanner over Profinet for Siemens S7-F safety PLCs. Each protocol provides safety-rated communications in which the scanner delivers zone status, diagnostics, and fault information over the network directly to the safety PLC, doing away with hardwired safety relay cascades in complex multi-scanner installations. These protocols are configured utilizing our free PC-based configuration utility.