Unlike conventional opto-electronic devices such as light curtains or laser scanners, a safe vision system can monitor multiple areas and detect foreign objects (such as a finger, leg etc.) within the viewing area, rather than detecting that a light beam has been interrupted.
There are two types of safe vision system available from Pilz Australia , namely, safe cameras (such as PSENvip) for press brake monitoring and safe 3D vision systems (such as SafetyEYE) for area monitoring.
A 3D safe vision system can monitor an area in 3 dimensions, compared with typical opto-electronic protection devices such as laser scanners or light curtain, which are 2-dimensional monitoring devices. With a 3D system the height, width and depth can be specified creating 3D monitoring zones anywhere in the viewing area, and the zones can be of any shape.
Current safety-related solutions have their limits. These limits are especially noticeable in case of a robot workstation comprising one or more robots and protected by safety fences.
To detect people entering the danger zone or remaining within it, the robots generally require additional protective devices such as light grids and laser scanners in conjunction with a gate entry interlock.
However, typical optoelectronic protective devices are unable to monitor zones, they monitor planes only. If there is no visual contact then the workstation must also be protected using pressure sensitive mats.
So uninterrupted monitoring of a robot’s operating range is only possible with a great deal of technical investment.
Another factor is that conventional protective devices immediately stop the robot in the case of danger. A restart costs time. With a safe vision system it can be different.
In this case a detection zone violation does not automatically lead to an emergency stop. Warning functions may be triggered when a detection zone is violated, so that the robot continues at safely reduced speed. An emergency stop will only be triggered if the worker enters the immediate danger zone.
The large number of different components and the complex wiring involved makes it expensive to safeguard a robot workstation, and also has a negative impact on its availability.
Not only can a safe 3D vision system increase the productivity, but also maintenance tasks can be simplified. Cleaning the production area can be a lot easier without the requirement of removing or manoeuvring around fixed guarding, saving valuable time and money.