Series Wiring of Limit Switches
Wiring the normally closed contact of the limit switch in series between the receiver's relay output and the contactor coil. That way, when the limit is reached, the coil circuit is opened directly and the movement stops independently of the state of the radio link.
The correct chain is: receiver relay contact → limit switch NC contact → contactor coil. In this arrangement, even if the control command is valid, the coil is de-energised when the limit switch opens and the contactor drops out. Limit protection no longer depends on software, pairing or signal quality.
- Wrong arrangement: wiring the limit switch only to a warning lamp, or using it as an information input on the control side. That means handing the cut-off function over to the radio chain.
- Direction split: the upper limit must cut only the hoisting direction; the lowering direction must stay operable. For this, the limit contact goes into the line of the corresponding direction coil.
- Multiple limits: limit contacts belonging to the same direction are wired in series; the movement stops when any one of them opens.
This approach is consistent with the control circuit and interlocking logic of the electrical equipment of hoisting machines and can be applied directly with the relay contact output of AXI receivers.
The context in which this term is used: Wireless Crane Remote Control Selection Guide