SPRY347 June 2022
ISO10218-1 specifies the safety requirements for industrial robots. According to the standard, an industrial robot shall be designed so that it complies with PLd with structure Cat3 as described in ISO 13849-1:2006, or so it complies with SIL 2 with a hardware fault tolerance of 1 (HFT=1) as described in IEC 62061:2005. Specifically, the industrial robot architecture must meet HFT=1 to ensure that a single fault in any of the safety-related parts of the control system does not lead to the loss of the safety function of the system. When a single fault occurs, the safety function is always performed and a safe state shall be maintained until the detected fault is corrected.
Considering the robot controller use case in more detail, there are several ways a dual-channel safety architecture (HFT=1) can be realized: