The purpose of the safety function is to disconnect the motor from the power supply. The protective devices on Ex equipment/products are within the scope of the ATEX regulations - Harmonized standard EN 50495:2010. Since IECEx does not have an applicable standard for complex safety devices related to explosion risk, for the time being, the certification of protective devices can only be performed according to ATEX standard. Also remember always to check the local regulations.
Many industrial variable speed drives contain ATEX certified safety functions with interfaces to PTC/Pt100 sensors, to implement over temperature protection of an Ex motor. In ATEX, protective devices shall be certified and marked similarly as eg, Ex motors. The marking can be found from the drive, but it is related to the drive integrated safety function only, and does not indicate that the drive has been tested and certified with an Ex motor.