Steppers are skipping steps

#1
Hi Jerome

Thanks for all your effort and time in creating such an amazing program. I purchased the HobbyCNC Foam Pro board with an 8kHz timer.
I finally got all my motors to run but sometimes find that they are skipping steps.
My configuration is:
CNCNet98.dll as I'm running on Windows 98SE
I have selected the Syncronize with External Timer and set a 8000Hz value. (as my board has its own timer)
Nb mm/pas = 0.005
Cut Speed = 18 thus Est mm/s = 2
Fast Speed = 15 thus Est mm/s = 2.35

When entering a cutting distance for example 30mm my CNC moves exactly 30mm, thus I know my Nb mm/pas is set correct. I also don't have a problem with speed using above setup. My only problem is sometimes I can see and hear the motors skipping some steps. Like I said this is a very random occurance as sometimes they run very smooth and sometimes not or they will start smooth then skip some steps and then all of a sudden run smooth again all in the same cut! Any idea as to what the problem can be?

Thanks
Collen

Re: Steppers are skipping steps

#3
I think i know what he means with hearing the lost steps.

I hear it too sometimes, but it is very minor loss. ( 1 step for me = 0,00625mm)
But it happens in GMFC too.

I think it is a app running in the background.

When i start moving my mouse around it gets worse.

Maybe my laptop is a little too old for this, but it has a nice LPT port, and my new one hasn´t.

Grtz,

snookie

Re: Steppers are skipping steps

#4
Hi Guys

Yes, its definitely 'something' running in the background....Last night I noticed that when I move my mouse I could hear the resonance in the motors. Also in Jedicut's Cut in Progress bar, as soon as a new progress bar is added you also notice this.

I've set my LPT port mode to both EPP & ECP and no difference. Problem seem to be processing that somehow interrupts to the LPT port.
Any idea how we can set the printer port dedicated for Jedicut?....I'm afraid I don't have enough knowledge on port interrupt requests and address resources :S

Thanks
Collen

Re: Steppers are skipping steps

#5
Hello,

Jedicut works well on old computer. Just let your mouse sleep a little when you're cutting :p

You can may be take a look at the list of the programm running on background. Maybe you can desactivate something ? An other idea : sometimes, if you try some other CNC program, they install driver which block Jedicut...
Jerome

Re: Steppers are skipping steps

#6
Hello,
I have the same problem. I tested the driver VisualCNC and CNCNet with my CNC Board which is compatible to the board of Ostermann (comman in germany). It uses the L298 chip and support half and full step. Without cuting I hear that the motor irregulary skip steps. Which communication protokoll ist used from the drivers? I would like to contact the dealer to ask about the communication protcol from the card. If I need another protocol, is it possible to get a new .dll?
Best regards
Frank

Jerome, thank you for the nice software, which is exact that I need for developing new aeroplanes.

Re: Steppers are skipping steps

#8
Hi Frank

The problem I have is definitely caused by interrupt requests on the printer port! It's not that big a problem for me and I don't really see any errors in my cuts although I mainly cut very small parts - Maybe on bigger cuts you might notice something?

Re: Steppers are skipping steps

#9
Dear Jerome,
thank you for your quick response. The dealer mentioned the software PC-NC or WINPC-NC on his homepage (Download section). On the follwing link are more information and in the "Online shop" you can find the 4 channel board (SM44PCV5) I use. Possibly more jedicut users are interested in the board, because the price is 111,50 Euro for the ready to use board with parallel port cable.
Best regards
Frank

http://www.gwr-elektronik.de/start.html
http://shop.strato.de/epages/61125483.s ... 5.1/RK2%22
Under "Beschreibung als PDF" you can download the instruction manual in german

Re: Steppers are skipping steps

#10
Dear Jerome,
according to my topic a few minutes before, I have some additional information. I just talked to the developer of the board. He said that the board works fine with a pulse duration (pulse width) over 10us in the communicatin protocol. Under 10us it´s not stable. Does this information help?
Best regards
Frank

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