The Return Fan track Output Controller module is designed to control a variable speed return fan in an air handler application. The return fan tracks the supply fan. The module has outputs for controlling a variable speed return fan.
The Supply Fan Percent Cmd is used as an input to the module and after passing through a span block is sent to the Return Fan Percent Cmd. By default, the span is set to mirror the Supply Fan Percent Command, but this can be modified by manipulating the low and high limits of the span block.