I have configured FLD so that two signals are on Instrument 1 and other two on Instrument 2. When I open Instrument 2 and go to Device Monitor it does not display any signal.
This problem applies generally to all control modules. Some devices contain parts "subdevices", such as signals in FLD, that cannot be used on two independent chromatography sets at once (two independent timebases). Usually it is not possible technically. The most recent control modules will show a warning during the configuration procedure when you attempt to split indivisible device between multiple Clarity Instruments.