Help with hy_gt_vfd

I think that for your case it is correct. In your case, for example, for a speed of 900, LCN sends a CMD 15, the VFDmod component applies 600/18=33.3333, resulting in 500, this value is the one that LCN sends. to the RS 485 port to the VDF, upon receiving it internally, if I have not been able to understand it, it returns and divides it by 600/18 to set that value to command the speed of the VFD, that is, 900 RPM that is achieved with a frequency of 15 Hz. In my case the difference is that the speed of my VFD is not limited and reaches 24000 RPM, that is why I apply 600/24. That's my interpretation, I don't know if I'm wrong.

Thank you for the explanation it makes sense to me now.  

Hi all again I am glad to say I have made so progress getting my Hy_gt_VFD working thanks to COFHAL's help.  I can now talk to the VFD without errors, but it still will not run the Spindle. I am hoping someone can figure out what I have wrong or missing.  here are my setup files.  when try to manually run the spindle by clicking the forward or review button after I hit stop the spindle tuns a bit then stops. I see the frequency and speed respond for a second in my panel then go back to 0.  Hitting the + button does not work vfdmod pins are showing increasing speed and frequency but not the spindle pins. I think I am close, but I can't figure out where the issue is.  
    

In SpindleRpmIn Put.
Multiplier=10000
Divider=300
And Craig_LinuxCNC_machine.ini SPINDLE
MAX OUTPUT=18000

Thankyou.  I will give that a try tonight 

It is still the same it connects when I try to run the VFD with the CW or CCW buttons the VDF responds I see a quick flash of a speed and the spindle turns a few degrees and that is it.  pushing the + buttons don't do anything Looking at the signals I don't see them changing ether I assume that there is something with the PIN setup.  The Communication is good I do not get any communication error.  Just no Spindle control.  Does anyone have any idea for me to try?