HY VFD and RS232>RS485 converter

Hi. I have a chinese huanyang vfd to control my spindle and decided to control it throug RS485.
The plan is to send/receive the data using the rs232 of the PC.
I've followed this
It seems on the scope that data is transmitted on txd pin and axis starts with no problem
Now i'm thinking to build the converter using a sn75176 driver and optocouplers because I'd like to opto-isolate the PC RS232 from the vfd.
Now the problem. Since comunication is half-duplex, how does the RS232 set the data direction of the comunication???
On the net I found this which seem good
www.kswichit.com/PC485/PC_Rs485.html
It uses the RTS pin to set the data direction, but checking with the scope it never changes its state. Neither any other pin, except TXD which transmits something i dont know at fixed intervals

my custom.hal
my custom_postgui.hal

you do not need a isolation it is alredy double isolated
you can use it to adapter as so many do

just hook it up and go for it

Ok.Done.
Now it's running fine.
Only thing I've done different is to change PD001 to 1, so I send speed only over the modbus and give the direction/run/stop from the p-port. That's because of how I use e-stop.
Now I'm trying to link a few signals to glade but the hal_vfd page is not clear on what are all signals.
linuxcnc.org/docs/2.7/html/man/man1/hy_vfd.1.html

I don't understand what these are
Is there a way to know if the vfd has tripped and what caused it, to link on a led in glade??
And the same to know the status of the output relays the vfd has?

I would guess that those relate directly to entries in the HY manual and that the author of the HAL component had no idea what they do either, if the manual doesn't explain.