There are actually 2 plugins made but this is the better one here:
Mach3 plugin for Huanyang VFD | Le royaume d'éole

the problem is that both of them do export the actual rpm's value from the vfd into the mach3 rpm dro oem code "39" which is displayed on mach main screen, this is useful for a milling but in a lathe it is displayed instead of my working single pulse index (the plugin do overwrite the index pulse data)
as a result even if the chuck is stopped the rpm displayed remains the same (just a fixed number based on the asked frequency)
I tried to contact the plugin programmer but no answer
what other work around can be made?