When collaborating robots need an enabling switch

Author: CEmarking TEAM | Last edited: 03.05.2020

In classic robot applications, a protective barrier separates man and machine in automatic mode to ensure the safety of employees. However, sometimes a person must also move it from inside the protective area - for example, to steer the robot precisely to a position to be approached. The person is then no longer protected. In this case, EN 10218-1/-2 requires a three-step enabling switch as an additional safety function.

Cobots can work side by side with humans in automatic mode without a safety fence. The prerequisite for this is a successfully completed risk assessment. That means:

Do Cobots need a three-step enabling switch as required by EN ISO 10218?

Cobots differ from conventional industrial robots because of these safety functions contained in the system. The answer to this question is given in the Technical Specification (TS) ISO TS 15066 "Robots and robotic devices - Collaborating robots". The following is defined there in Section 5.4.5:

... if a risk assessment determines that the risk reduction normally achieved by the use of an enabling device would alternatively be achieved by inherently safe design measures or safety-assessed mitigation functions, the handheld robot controller may be equipped for a collaborative robotic system without an enabling device.

This means: If the robot and the application as such are sufficiently protected, no enabling switch is required. However, this definition leads to further questions:

If the answer to these three questions is YES, then their robot system can operate without an enabling switch, since the system's always active safety functions replace the enabling switch.