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Author Topic: Ref all home -> goto zero Overshoots/limit activation  (Read 1053 times)

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Ref all home -> goto zero Overshoots/limit activation
« on: December 05, 2018, 07:38:49 AM »

I have recently bought a cnc3040....   aaaaaaand here the trouble:

Machine: Laptop 64 bit windows 7 !!!

MACH3: DEMO version !!!

USB RNR Motion controller (RNR.dll driver put in plugin folder)

End and limit switches on all axes
Pulloff of 0.5mm

Cabling: Nothing seems to be shielded: all the wires, steppers and switches are just wraped in protective plastics from controller box down to the machine.

The machine "Ref All Home" fine and zeros the x,y,z DRO's. (during the ref all home the "abnormal condition" is lit, but it turns green as the DRO zeroe's) DRO is in zero in both "machinecoordinates active and deaactivated.

If I then jog to nx,ny,nz and hit "Goto Zero" my machine either overshoots, hits the limit or stops before the 0 in either direction. And now I can press the "goto zero" 3-7 times before it "shoots" right and hits the 0,0,0...

If I then instead jog around and then just jog my way back to zero, it hits the DRO 0,0,0 perfectly
(soft limit is on)
I also tested the pulse frequency in the motortuning.

I have not yet tested to update the Control panel Device manager "computer" ACPI x64-based pc to "normal PC"

-I just want to know if it is normal to expect an accurace of hitting home from +1,5 to -0,5mm.. ?
- Or if my USB motion control board is just...$@£$$$ ? (it might also only work with the mach version it was delivered with)
- It might aswell be the driver and the 64 bit that tricks me?

I have a new paralleport BOB and 3 step drivers ready, hence I do not trust the machine one bit in its current state...
Re: Ref all home -> goto zero Overshoots/limit activation
« Reply #1 on: December 11, 2018, 01:55:17 PM »
So I did a bit more testing with a new computer it would seem that the error arises when the controller has been on for about 60 minutes.
If I try to go to 100 mm the Machine goes 105 ish..

But it seems odd to me that the dro reads 105 when I put in 100,
As I understand the dro shows the pulses sent by the program, but why would mach send out 105 when asked for 100...
It would make more sense to me if the controller was shot so that mach would read 100 but the controller misfired the last 5...

I'm wirering up my parallel Bob later tonight....grrr