Carry out the following working steps regularly:

    Clean the signal lamp covers.

    Check whether the signal lamps are in order. Each signal lamps is lit by LEDs and has a service life of around 50000 hours.

    Clean the lenses of the light barriers.

The light barriers are used for transmitting the release signal by means of light path between the two cranes with tandem control system. If they are soiled the signals cannot be transmitted and the cranes come to a standstill.