During each relevant journey, the contactor monitoring checks whether the energy flow to the motor or valves drops at each operational stop. If one of the travel contactors does not drop out, the lift is prevented from starting again. (safety circuit interruption)

The safety relay from TYCO/Schrack, type SR4, is used for the safety circuit.

The contactor monitoring must be protected from water, conductive dust and condensation.
The contactor monitoring must be installed in a housing or in its own switch box that corresponds to at least IP23.
The main/auxiliary contactors must conform to EN81 standard.
Additional instructions for installation, operation, maintenance are not required.