Solved Drift on 6090 with Weihong NK105 and Leadshine M552


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Thread: Drift on 6090 with Weihong NK105 and Leadshine M552

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    Default Drift on 6090 with Weihong NK105 and Leadshine M552

    I just solved a problem that has been plaguing me for nearly 2 years so I thought I would share!

    My 6090 router from Jinan iTech has been slowly losing position in all axes, especially on complex jobs. This is most obvious in circles and arcs being non-concentric, and the Z height slowly dropping when doing engraving work.

    The solution was to set a jumper in each of the M542 stepper drivers to change the pulse logic to negative. The jumper is marked 'J1' and is in a little bank of 6 header pins, visible only by unplugging the driver then removing the plastic cover.

    Now it is fixed, I am pretty impressed by the accuracy and versatility of the machine - from ripping up slabs of plywood to engraving tiny details on PCBs.


    Background -

    The machine runs on a Weihong NK105G3 DSP, with 3 x Leadshine M542 stepper drivers. I use mainly ArtCam and also Eagle plus PCB-Gcode.

    I first noticed this effect particularly when using 'area clear' toolpaths on holes.

    I managed to contain the problem by switching to a finer micro-stepping resolution and avoiding area clear toolpaths, good enough for most work.

    But - I have been running some fine PCB work recently and accumulated errors of near 1mm were terminal!

    The error was repeatable - each time I ran the same job I would get the same result - but otherwise confounding as there was no obvious skipping, backlash or other failures I could see.

    Returning the machine to relative zero, would end up in a different position to where it started, even though the readout showed 0.000, 0.000.


    The technical bit -

    The DSP controls the stepper drivers through 2 pairs of control wires sending 'step' and 'direction'.

    There are a few different schemes but one variation is 'pulse logic' which can be positive, meaning that each step occurs as the voltage rises from 0 to 5V; or negative, meaning each step occurs as the voltage falls from 5V to 0.

    If you look in the NK105 manual on page 83 there is a diagram showing this - the section relates to a servo driver but this is a clue as to what the NK105 is outputting (note the manual says to choose # 2, single pulse stream negative logic).

    The M542s on the other hand are set to positive logic by default, at least mine came that way. Page 3 of the M542 manual sets this out.

    The repercussion of this is that every time there is a direction change, one micro-step gets counted in the wrong direction. On a complex job, this adds up to a visible error.

    Those area clears involved lots of little concentric circles and therefore lots of direction changes!

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    Default Re: Drift on 6090 with Weihong NK105 and Leadshine M552

    Hi,

    We are looking at getting a CNC with a Weihong NK105G3 DSP controller. Do you have a post processor for it that might work with Inventor HSM? do you know if there is one available?



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    Default Re: Drift on 6090 with Weihong NK105 and Leadshine M552

    Thanks Mary, but Inventor / HSM needs a post-processor to work with NK105 G2 or G3 right? Do you work with Weihong?



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    Default Re: Drift on 6090 with Weihong NK105 and Leadshine M552

    Hi
    I have exactly the same problem with Weihong NK105 and Leadshine MA860H
    Can you please tell me how exactly should I change "J1" jumper pulse logic?
    Thank you in advance



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    Default Re: Drift on 6090 with Weihong NK105 and Leadshine M552

    I am having problems on the Y axis drifting(see attached). Can you show how you cured the problem?

    Mine is Weihong NK105G2. I having a problem with the spindle gears. When turning on the spindle the the inverter reads the following when cycling through the gears:-

    Gear Inverter
    0 0
    1 150
    2 320
    3 470
    4 0
    5 150
    6 320
    7 470Drift on 6090 with Weihong NK105 and Leadshine M552-20170507_151106-jpg



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    Hi Archil

    Well it has been a year or so but I just found your message. Did you ever solve this problem?

    Looking at the ma860h manual it looks like you need to add a jumper to J3 in your case to achieve the same setting change (active at falling edge)

    See page 4 http://www.leadshine.com/UploadFile/Down/MA860Hm.pdf


    Quote Originally Posted by Archil View Post
    Hi
    I have exactly the same problem with Weihong NK105 and Leadshine MA860H
    Can you please tell me how exactly should I change "J1" jumper pulse logic?
    Thank you in advance




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    Hi bigz

    Well better a year later than never did you ever solve your problems? The drift you show here is a lot more severe than what I was experiencing so it might be a different issue,

    The spindle gear problem however - I also had but fixed. The cause is that the 3 wires from the NK105 to the vfd for speed control were connected incorrectly. These are marked S_0, S_1 and S_2 and need to connect to corresponding lines on the VFD (markings will depend on your model of VFD).

    I hope this gives you a clue!



    Quote Originally Posted by bigz1 View Post
    I am having problems on the Y axis drifting(see attached). Can you show how you cured the problem?

    Mine is Weihong NK105G2. I having a problem with the spindle gears. When turning on the spindle the the inverter reads the following when cycling through the gears:-

    Gear Inverter
    0 0
    1 150
    2 320
    3 470
    4 0
    5 150
    6 320
    7 470Drift on 6090 with Weihong NK105 and Leadshine M552-20170507_151106-jpg




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    Default Re: Drift on 6090 with Weihong NK105 and Leadshine M552

    Hi Loska

    Thanks I fixed the drift with your method. I will have a look at the inverter thanks.

    Have you had any luck wih 4th axis?

    Happy New Years



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Drift on 6090 with Weihong NK105 and Leadshine M552

Drift on 6090 with Weihong NK105 and Leadshine M552