[mactec54]

the hz difference issue is not critical now, the reverse is
i am using this bob here https://warp9td.com/images/BOB_Vendo...line/ST-V2.pdf
it seems impossible to reverse using it as it uses only 1 relay
so I was wondering what i can do to reverse by g code using this bob with least work
a suggestion that i got is to replace the relay with another SPDT relay so it switches between reverse and FW, speed = 0 also equal stop, that is an option but i am not very happy with it
perhaps add another relay but i am not sure how to wire it and use another unused pin
the motor is an 1.5kw AC 3ph induction motor, at the moment everything works fine, on/off via mach3 relay, speed control via mach as well, only the reverse is via an external switch to the vfd block terminal X2+com

There is part of your problem you need 2 Relays ( 1 ) for FWD and ( 1 ) for REV
You can see this in your manual

DI1 K1 FWD

DI2 K2 REV

COM

These are the connections you need for FWD and REV

You will have some parameters to set as well

I see you are using a different terminal reference X2 have you changed the VFD Drive you are using

That Breakout Board is not going to do what you need, you want one with 2 Relays on