This thread appears to have strayed off track from its original intention,
The main idea behind this thread was to demonstrate how easy it is to interface the Digital output of the G540 to any VFD or controller PLC that uses a source input in order to use the G540 sink output for FWD command signal.
This method is intended to eliminate or exclude the alternative to an intermediate relay.
Which incidentally the SuperPID Triac Spindle controller manual also shows as the recommended way.
The device interfacing the G540 to has to be able to either use the typical opto input that has a source voltage or one that can be configured for source or sink, the Huanyang for example has a set (non-configurable) sourced PLC input.
Any further posts that are not relevant will be given their own thread.
Al_The_Man