linuxcnc 'hangs' when using spindle

Hi All,

I have come across a very strange system behaviour with my lathe running on LINUXCNC 2.8.4.1
If I run this G code for example below, the axis stops "responding" after the spindel start command (S1000 M3) is exeuted (and the motor is running) or at least NOT executing the G46 command after the spindel start command (S1000 M3).
(example from lathe_pawn.ngc)
G21
G64
G18 G8
G00 X13.5 Z1.0 S1000 M3
Z0.488
G94 G01 X-1.0 F50.0   --> at this command linuxcnc stops running the program

If I remove the "S1000 M3" command from the programm, the program runs flawless.
I have seen a similar behaviour when I manually switch on the spindel (Manual Control tab in AXIS GUI) and then execute a move command like "G01 X20 Y-1 F50" from the MDI tab in the AXIS GUI

If I don't run a program or execute commands in MDI, I can have the spindle running and axis moving in manual control mode.

I have no clue what is going on so any help is very much appreciated

Thanks in advance
 

Thanks for the hint.
Indeed it seems to be related to "Spindle At Speed" or better said, Spindle not being at speed....
For now I disabled this spindle at speed calculation checkbox and the spindle at speed GUI checkbox in the setup and this seems to 'solve' the problem for the time being...
Problem behind it is that my physical RPM is not really matching the linuxCNC RPM value. This needs to be fixed so I can use the "Spindle At Speed" function again (as I think it is a useful function)

If I ask for a spindle speed in linuxcnc:
S1000 M3 --> I get ~223 RPM
S3000 M3 --> I get ~677 RPM
S4000 M3 --> I get ~900 RPM

Not yet clear how to solve this, but I have more challenges with my spindel to solve