Prevention of Unintended Operation
The design requirements that prevent a motion the operator did not intend from starting, and one of the explicit headings of IEC 62745. Pressing the button of a transmitter put into a pocket, dropping the device, or a command going to the wrong receiver are addressed within this scope.
Because the operator can be far from the machine with a wireless remote control, an unintended command is a far more serious risk than with a wired system. The measures are built in three layers: hardware, logic and organisation.
- Hardware: starting that requires an activation switch or a two-handed action; buttons recessed into the housing or shrouded.
- Logic: not starting motion if a button is held when the device is switched on, that is, a start interlock; automatic sleep after a defined period of inactivity.
- Addressing: each set carrying its own identity code, so that the command from the remote of a neighbouring machine is not accepted.
- Organisation: storing an unused transmitter in a locked cabinet and keeping records at shift handover.
The most frequently seen breach in the field is the transmitter rubbing against something while hanging from a belt and pressing a button. Momentary control logic reduces this risk but is not sufficient on its own; keeping the transmitter in a passive state when nobody is at the machine is part of operating discipline.
Context in which this term is used: Wireless Crane Remote Control Selection Guide