[ Vfdmod ] An easy VFD control over MODBUS RTU

Well, possible reasons are:
a) wrong control register address and / or wrong control world values. See your device manual to be sure.
b) wrong HAL connections. Show your HAL files please, I'll try to help.

I think the registers are ok - sending the value 0x0012 to the address 0x2000 causes the start to the right, etc.

Your custom.hal should be:
If output speed will be wrong take your attention to Multiplier and Divider parameters in vfdmod ini.

I changed these two lines - I forgot to rename the pins in linuxcnc 2.8 before. I left a multiplier 1 and a divisor 1 everywhere, so they shouldn't affect the values.
Now the program gives a signal to the inverter and the inverter switches to RUN and FOR but after a second there is a communication error again (code 110) and the connection is red. Now I set the minimum speed to 50 and this value is given and after pressing the inverter direction icon, the motor starts with the minimum speed but stops responding to subsequent commands and I have a connection error.
Is it possible that the vfdmod program is using a log write function not supported by my inverter? I checked that I can use function 06 and multi-save 10.

My config file:

Thanks again for your interest and help. I am very beginner, hence problems at every step

Now diode for Spindle at speed is green

Zbysob1 wrote: Now the program gives a signal to the inverter and the inverter switches to RUN and FOR but after a second there is a communication error again (code 110) and the connection is red.

It looks like the reason is electrical noise, like here: forum.linuxcnc.org/24-hal-components/391...communicaiton#168822

Zbysob1 wrote: Is it possible that the vfdmod program is using a log write function not supported by my inverter?

No, I don't think so.