I too was unable to find a manual on the exact unit that you have, but agree that
the instructions should be the same as for other Huanyang VFDs in that series.
The PMDX-407 uses an analog control voltage and simulated switch contacts
to control the VFD, so it interfaces in a very different manner.
The connections required are:
PMDX-407 VFD
------------------------------
Aref 10V
Aout VI
Agnd ACM
RUN FOR
COM DCM
You must also set two parameters in the VFD to instruct it to listen
to the control terminals instead of the front panel. They are:
PD001 must be set to a value of 1
this selects External Terminals as the source of the run command
PD002 must be set to a value of 1
this selects External Terminals as the source of the operating frequency
Instructions for programming parameters in this VFD are not very
clear in the manual. I recommend looking at this YouTube video:
https://www.youtube.com/watch?v=a-8NR5XY8CQThe programming example starts at about 5:10 into the video.