Tdk lambda din rail power supply drf hl series tdk lambda drf 240 24 1hl the tdk lambda drf 240 24 1hl is a din rail power supply that has been certified for use in potentially explosive atmospheres and marine applications the product has been tested to isa 121201 iecen 60079 02011 iecen 60079 152010 and guidelines for the performance of type approvals test requirements for electrical electronic equipment and systems vi 7 2 the power supply carries a 5 year warranty and is