Limit switch is a position switch having positive opening operation.
Positive opening operation (of a mechanical switching device) is an opening operation which, in accordance with specified requirements, ensures that all the main contacts are in the open position when the actuator is in the position corresponding to the open position of the device.
Position switch is a pilot switch the actuating system of which is operated by a moving part of a machine, when this part reaches a predetermined position.
Pilot switch is a non-manual control switch actuated in response to specified conditions of an actuating quantity. Note – The actuating quantity may be pressure, temperature, velocity, liquid level, elapsed time, etc.
Control switch (for control and auxiliary circuits) is a mechanical switching device which serves the purpose of controlling the operation of switchgear or controlgear, including signalling, electrical interlocking, etc. Note – A control switch consists of one or more contact elements with a common actuating system.
Mechanical switching device is a switching device designed to close and open one or more electric circuits by means of separable contacts. Note – Any mechanical switching device may be designated according to the medium in which its contacts open and close, e.g. air, SF6, oil.