Digital point level switch - is esp. for controlling level of material in container which includes source of gamma ray transmission being attenuated by material

摘要

A first counter accumulates pulses generated at a rate inversely related to the level of the material up to a first predetermined total. A second counter accumulates clock pulses up to a second predetermined total representing a fixed counting interval. The counters are connected in a race circuit wherein the one to reach its predetermined total first resets both counters and controls the face circuitry. The first counter sets a control circuit to indicate a low level condition or to activate an alarm, and the second counter resets the control circuit to indicate a high level condition.