good morning
I have a problem with the spindle speed that I cannot solve, without loading the gcode I turn on vfd then the spindle I press the "+" key and it increases the speed a little and up to here it is ok if I load the gcode and the speed is "M3 S10000" I start working and press the "+" key the speed doubles, I would like (if possible) that it increases slightly there is a way to set
the increase in speed?
I thank those who can help me, I hope I have explained.

Mach 3 or Mach 4?

mach3  ver.3.043.062

OK, now we know more about the software, what hardware configuration do you have?  How is the VFD speed controlled from your computer?

thanks for the answer, I have a 4 axis tb6600 vfd card connected to the Modbus RS485 com port, to increase and decrease the speed I use the "+/-" keys, I state that first everything worked regularly then (I don't know why) it arose this problem. I enclose xlm

screen

So essentially the speed is controlled by a modbus connection between computer and VFD, right?  And when you say +/- keys, I assume you mean the spindle speed override on the mach3 screen?

just the speed is controlled by a modbus connection between computer and VFD, the +/- keys' override the spindle speed on the exact mach3 screen

Try changing the %S DRO to say 10 rather than 100.

I tried to set 10 in the dro but it always returns to 100 I don't know if there is to set it somewhere else