Unfortunately there is no black and white answer to this, nor are there any pre-printed forms.
In accordance with BetrSichV, the competent person must find out himself how often the inspection is needed and what the scope of that inspection should be. Pilz GmbH and Co. KG, Ostfildern, operates an independent test laboratory accredited by DAkkS in accordance with ISO 17020. It is able to inspect light grids.