| 摘要 |
Apparatus for indicating level of material (16) in a vessel (12) that includes a probe (14 or 70 or 100 or 130 or 140) for placement in the vessel at a position corresponding to a desired height at which material level is to be detected. Electronic circuitry (18 or 74 or 108 through 116 or 136 or 152) is coupled to the probe, and is responsive to operating characteristics of the probe for sensing a change of such operating characteristics between a first operating characteristic at which material is spaced from the probe, and a second operating characteristic when material is adjacent to the probe. The electronic circuitry is contained within a closed housing (20) mounted on the probe, and is connected to a source (52) of electrical power positioned remotely of the vessel. A pair of status lamps (56 and 48) are positioned on the housing, and are coupled to the electronic circuitry for respectively indicating application of electrical power to the circuitry and detection of one or the other of the operating characteristics at the probe. A reed switch (64) is positioned within the housing, and is responsive to juxtaposition of a magnet (68) externally of the housing for simulating one of the operating characteristics of the probe independently of actual material level at the probe. <IMAGE> |
