A selector is a converter that takes two signals, A and B, and selects either the higher or lower signal to output an analog signal proportional to the selected input.
A “high selector” (high signal selector) chooses the higher of the two signals, while a “low selector” (low signal selector) chooses the lower signal.
For example, in air conditioning control systems that regulate valves based on signals such as temperature and humidity, the selector takes in two temperature signals from different sensors and selects the appropriate signal.
There are also cases where a high selector is used for furnace wall protection or for pressure control.
