| 摘要 |
The invention provides apparatus for detecting the position of a float in a flow or level meter, comprising a series of transceivers (paired transmitters and receivers, such as LEDs and phototransistors) disposed along a selected range of the float's intended operating movement. Selected transceivers have their transmitter or receiver oriented out of functional alignment with the corresponding receiver or transmitter of the adjacent transceivers to provide immunity from cross-talk between adjacent transceivers. A helical arrangement is suggested. Variants of the device use infra-red transceivers to provide immunity from incident visible light. Several receivers may correspond to a single transmitter. |
