Workable safety with laser scanner

To create a safe work situation, robots and other "dangerous" machines should operate exclusively behind a sturdy fence. However, this usually does not provide a workable situation and it is more convenient to use a safety laser scanner. This infrared-based rotating sensor continuously 'scans' its surroundings, detecting the presence of people in the 2D plane. With this, safe workability - or workable safety? - to be created.

The construction of Pilz' safety laser scanner PSENscan includes a housing that houses an infrared laser. This laser rotates with an opening angle of 275° and performs a measurement every tenth of a degree. Based on the time it takes for the laser beam to bounce back, it can be determined whether people are unintentionally entering this area. The response time is only 62 ms.

If the safety laser scanner does indeed detect people, it communicates this to the (safety) control system that takes the desired action; programmed by the user. For example, it can stop the entire machine or line, reduce robot movements to a safe speed or otherwise. Often accompanied by acoustic or optical warning signals.

Zones

To prevent machines from stopping immediately when people move near them, it is possible to set up two zones. The zone in the immediate vicinity of the machine is the "safety zone. This is actually dangerous and leads to the shutdown or controlled stopping of the machine. The safety laser scanner can monitor a safety zone of 3 or 5.5 meters. Around this, an additional "warning" zone of up to 40 meters can be set. There is no immediate danger here, but people who enter this zone are warned by sound or light signals. When they subsequently leave the warning zone, no serious dangerous situation arises.

One safety laser scanner can monitor up to three individual protection zones simultaneously; in the process, up to seventy configurations can be switched and series switching of up to four scanners is possible.

Static and dynamic use

The safety laser scanner can be used both statically and dynamically. In static application, the sensor stands at a specific location and monitors - in 2D - the area around a machine or robot. Mobile area security can be achieved by placing the safety laser scanner on an AGV (Automated Guided Vehicle) or BTS (Driverless Transport System). These autonomous systems drive around freely in space to, for example, take products away from machines or bring in parts. If people walk in their range, they will slow down - in the warning zone - or come to a complete stop. Again, light and sound signals can warn those present that they are getting too close.

In addition to stationary and dynamic area security, the security laser scanners can also be used for access monitoring. In addition, they can be used widely and versatile due to, among other things, the temperature range of -10 to 50°C and the compact housing that is easy to integrate. They also have a removable memory module that maximizes the availability of the security laser scanners. 

PNOZmulti

The safety laser scanner comes standard with a configurator that allows the user to set zone dimensions, speed of response and sensitivity, among others. The signals generated by the safety laser scanner can be passed back to a (safety) controller such as the PNOZmulti. This control ultimately ensures that the desired action is taken as described earlier. 

Also, the controller is responsible for a safe restart. This can occur automatically and independently when the safety laser scanner no longer detects people. But it may also require a technician or other employee to come on site to assess the situation and give the "safe" sign.