Please help - missing steps ... Mach3

[emilvv]

I have no more ideas for my problem ... PLEASE HELP !!!

What I want to eliminate .... When I moving Y axis by JOG ... after 10 - 20 or 30 cm of movement ... and when I hold the stepper motor by hand .. I fill strange, fast, single motor stall for very small period of time . This is as losing steps ..... When add dial indicator to the axe after some movements .... I lose 0.1 mm linear accuracy ... for 1-2 and more hours will be about 5 mm .... maybe

The sound is like a little, fast "knock" ....

What I did to eliminate the problem, noise .. losing steps ...
I tried many combinations

- 2 PC with Mach3 + LPT to the drivers. ( Acer 2 GB, 3 GHz.... Win XP .. ) and Cel 2.4 GHz, 256 MB ... Win XP
- 2 types of drivers - DQ860MA + Purelogic driver PLD8220-G2
- 2 power supplies ...
- 3 types of stepper motors - nema 23 - and 34 x 2...
- long shielded cables .. and short ...ones .
- Ground pipe in earth with cable to all shields .... cases ....
- tried all BIOS LPT modes EPP etc ..
- kernel mode - 25 and one level up KHz
- LPT direct cable to driver and thru BOB PCB card ....

With single G code - Y500 F500 .. after some mm I fill the same issue ...

When unattached motor is on the table ... the problem is the same ...

I have single phase 220 AC voltage ....

If someone have any ideas ... wiring drawings - please send it ... THANK YOU !!

Emil

[magicniner]

With all the different hardware options you've tried without resolving the issue I'd guess that something may be amiss in your motor tuning, you can have problems with too fast or too slow and if acceleration is too high or too low.

- Nick

[routercnc]

I had this problem a long time ago and it was caused by running the all-in-one system3 driver/Bob board at 30V. Dropped to 27V fixed the problem.
But you are using good seperate drivers so should be ok. What Bob are you using and what voltage is going to the drivers? Is it overheating?
Also tighten all screw terminals

[emilvv]

Hello,

Problem is not resolved ... But I have one more issue to check .. this evening .... :)

My motors acts like - http://www.woodworkforums.com/showthread.php?t=167883
( only on 200 .. 300 mm of movement .. not on every rotation .. )

I have XP optimisation.txt file with step by step guide how to setup PC before Mach3 installation ... but maybe I miss this step for switching to standard PC .... and this cause this signal spikes on LPT - missing steps and stalling for small periods ...

So, I will check and if this is a problem will post the results .....

I have 2 core CPU and I hope switching to Standard PC ... will fix the problem ....

THANKS TO ALL OF YOU !!!

Emil

[emilvv]

Hello,

Problem not resolved :(

What I did ....

1. Reinstalled XP PRO ...

2. Applied all steps from XP optimization.txt ....

3. Installed Mach3 + licence file

Started, but the same problem ... on every 200 - 300 mm movement motor 'knock' for a less than a second ... maybe 0.1 s ... :( I can feel the 'knocking' by my hand .....

Attached Win XP device manager screens - why I have 2 standard PC in my device manager .... is it normal ???

Any ideas .. ? Please help

Emil

[JAZZCNC]

What voltage do you have coimng out of the PP.? This problem sounds very much like PP is low power probably 3V type. This will cause the problem you are having because there isn't enough voltage difference between HIGH/LOW.

Also one more thing that can cause this and in some way related to the above is if your Step pulse is on the wrong edge of the pulse. ie: On the down slope(falling edge) when the controller is pulsing on the up slope (rising edge). This affectively puts the timing out and you'll loose one step with every direction change.
To test this for each Axis just write some G-code which moves the axis Back n forth small amounts but 1000's of times very fast.
ie:
G0 x10
x0
x10
x0

Copy and paste into a file to make several 100 lines. Make a Mark before starting and run the file. It should return and if it doesn't then you are on the wrong edge of the pulse.

Some drives will let you select the rising or falling edge, Some won't. To Force or change the edge just toggle the Active Low in Motor outputs. This will reverse the motor direction. So goto Homing and Limits and Click Reversed for that axis.

Try and let us know.?

Or better still do your self and machine a favor Dump the PP and get your self a external motion controller.!! . . . You won't regret it.

[njhussey]

I had a knock on my X axis today when changing direction sometimes, turns out the grub screws holding the pulley on the stepper shaft were loose and slipping. I'd put one jnto the stepper shaft keyway and thar was rattling back and forward....until it too slipped.

[emilvv]

Hello,

Clive, maybe you are right ... I have free time just to check LPT voltage - it is 3.3v on both PCs ...

I didn't check it before, because using one of the PCs with my bigger CNC machine I didn't have any problems for years !! ...
The same drivers on all machines !! ..

But when using it in another place / room I received the problem with both PCs -

So .....

Machanics is not an isuue ... motors knock on the table :) .. not connected to the machine ...

My plan - to add 6N137 fast opto - as opto and also as logic level 'converter' .. :)

( also I have them on 'stock' :) )

When I finish will write here the results ....

Thank you all of You !!

Emil

[Clive S]

... I have free time just to check LPT voltage - it is 3.3v on both PCs ...

I didn't check it before, because using one of the PCs with my bigger CNC machine I didn't have any problems for years !! ...
The same drivers on all machines !! ..

Ah but was you using the same BOB. The better BOB's level shift the 3.3V back up to the 5V and then generally all is well. Good luck with the investigation . Clive

[DuffelBuffelWuffel]

EdingCNC is quite a nice controller. Also affordable. Will work witout issues in Ethernet or USB. This takes little setup and works good.