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Thread: Taig CNC-Controller Replacement-Dynomotion Suggestion

  1. #41
    Member PeterTheWolf's Avatar
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    Default Re: Taig CNC-Controller Replacement-Dynomotion Suggestion

    Quote Originally Posted by TomKerekes View Post
    .........

    If you were to choose IO 34 or 35 (pins 15 or 16) there aren't any pull down resistors so the full 16ma would be available. Under a load of 5ma (instead of 16ma) the output would likely be higher than 2.4V but still there is no guarantee it would be 3V or higher. Most likely it would be. You could verify with a voltmeter if it actually is 3V or higher.
    This works. I am getting 1.5mV on KFLOP JP6 Pin 16 (IO35) with this relay connect and 3.27VDC on KFLOP JP6 Pin 16 (IO35) when I turn it on in Kmotion Digital I/O screen and the relay is pulled in.
    Thanks Tom ...........

    Taig CNC-Controller Replacement-Dynomotion Suggestion-5v_relay_kflop_wiring-jpg Link to Word Doc.



    Taig CNC Machine Quick Links
    ....
    ....

    KFLOP Power Suppy

    Stepper Motor Power Supply Used

    Stepper Motor Used on Taig

    Taig CNC Machine Counter Weight Design

    Taig CNC Machine Counter Weight Design - 3D STEP File

    Word Doc. of my Calculation for the Trajectory Planner

    Word Doc. E6 Optical Kit Encoder

    Relay Connection to KFLOP JP6 Pin 16 (I/O 35)

    ....
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  2. #42
    Member TomKerekes's Avatar
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    Default Re: Taig CNC-Controller Replacement-Dynomotion Suggestion

    Great. Thanks for taking the time to post back.

    Regards
    TK http://dynomotion.com


  3. #43
    Member PeterTheWolf's Avatar
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    Default Re: Taig CNC-Controller Replacement-Dynomotion Suggestion

    Quote Originally Posted by TomKerekes View Post
    Hi Peter,

    Higher resolution is always better until you exceed the count rate of the encoder input at maximum RPM. KFLOP can conservatively accept 1 million quadrature counts/second.

    2000 cycles/rev at 2000RPM would be:
    2000 x 4 x 2000 / 60 = 266K counts/sec

    And at 20 TPI would give a resolution of
    20 x 2000 x 4 = 160,000 counts/inch (6.25ui)

    I will not be able to use Linear Glass Scale on the Taig ... just not enough room for mounting it on the X-Axis.

    So, I will be going with the US Digital E6 rotatory encoder.



    Tom,

    If more is better and I will max. out at 1000 RPM with these stepper motors,
    shouldn't I use an encoder with 4000 CPR?

    Another question I have is, should I be configuring these encoders with the "Index" or "No Index"?

    Thanks,



    Taig CNC Machine Quick Links
    ....
    ....

    KFLOP Power Suppy

    Stepper Motor Power Supply Used

    Stepper Motor Used on Taig

    Taig CNC Machine Counter Weight Design

    Taig CNC Machine Counter Weight Design - 3D STEP File

    Word Doc. of my Calculation for the Trajectory Planner

    Word Doc. E6 Optical Kit Encoder

    Relay Connection to KFLOP JP6 Pin 16 (I/O 35)

    ....
    ....



  4. #44
    Member TomKerekes's Avatar
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    Default Re: Taig CNC-Controller Replacement-Dynomotion Suggestion

    Hi Peter,

    If more is better and I will max. out at 1000 RPM with these stepper motors,
    shouldn't I use an encoder with 4000 CPR?
    4000 cycles/rev would be:

    4000 x 4 x 1000 / 60 = 267K counts/sec

    and should work fine.


    Another question I have is, should I be configuring these encoders with the "Index" or "No Index"?
    An Index pulse can help with more accurate homing. You would first search for a home/limit switch and then search for up to one revolution for the index pulse. Its up to you. If you include the Index pulse output you can always just not connect it and not use it.

    Regards
    TK http://dynomotion.com


  5. #45
    Member PeterTheWolf's Avatar
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    Default Re: Taig CNC-Controller Replacement-Dynomotion Suggestion

    ..............
    ..............
    ..............

    Tom,

    I am using the E6 Rotary Encoder on the back of one Stepper motor for testing.

    I have put together of HTML link for a Cable Pinout from the Encoder to KFLOP via RJ45 and a C46 Differential to Single Ended Converter (from Welcome to CNC4PC).

    Can you please double check my pinout?

    My main concern is the last image of the HTML Link to ensure I am understanding the connection to KFLOP.
    This is only for one axis; however, the last RJ45 connection to KFLOP will be with all three axis.

    Taig CNC-Controller Replacement-Dynomotion Suggestion-004_rj45_breakoutboard_to_rj45_end_for_kflop-jpg



    Taig CNC Machine Quick Links
    ....
    ....

    KFLOP Power Suppy

    Stepper Motor Power Supply Used

    Stepper Motor Used on Taig

    Taig CNC Machine Counter Weight Design

    Taig CNC Machine Counter Weight Design - 3D STEP File

    Word Doc. of my Calculation for the Trajectory Planner

    Word Doc. E6 Optical Kit Encoder

    Relay Connection to KFLOP JP6 Pin 16 (I/O 35)

    E6 Encoder PinOut to KFLOP PinOut


    ....
    ....



  6. #46
    Member TomKerekes's Avatar
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    Default Re: Taig CNC-Controller Replacement-Dynomotion Suggestion

    Hi Peter,

    That seems correct to me.

    But it isn't clear that GND and +5V from KFLOP are being supplied to all the encoders (C46) pins 1 and 2.

    Regards
    TK http://dynomotion.com


  7. #47
    Member PeterTheWolf's Avatar
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    Default Re: Taig CNC-Controller Replacement-Dynomotion Suggestion

    Quote Originally Posted by TomKerekes View Post

    ........

    But it isn't clear that GND and +5V from KFLOP are being supplied to all the encoders (C46) pins 1 and 2.
    Yes .... I should have depicted this as well , I was thinking I would connect to the RJ45 break-out board Pin #2 & Pin #1 with the use of KFLOP JP6-Pin #1 for +5VDC and KFLOP JP6-Pin #8 for Ground, respectively.

    Do you see any issues with this?

    Thanks,

    Taig CNC-Controller Replacement-Dynomotion Suggestion-004_rj45_breakoutboard_to_rj45_end_for_kflop-jpg



    Taig CNC Machine Quick Links
    ....
    ....

    KFLOP Power Suppy

    Stepper Motor Power Supply Used

    Stepper Motor Used on Taig

    Taig CNC Machine Counter Weight Design

    Taig CNC Machine Counter Weight Design - 3D STEP File

    Word Doc. of my Calculation for the Trajectory Planner

    Word Doc. E6 Optical Kit Encoder

    Relay Connection to KFLOP JP6 Pin 16 (I/O 35)

    E6 Encoder PinOut to KFLOP PinOut


    ....
    ....



  8. #48
    Member TomKerekes's Avatar
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    Default Re: Taig CNC-Controller Replacement-Dynomotion Suggestion

    That should work.

    Regards
    TK http://dynomotion.com


  9. #49
    Member PeterTheWolf's Avatar
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    Default Re: Taig CNC-Controller Replacement-Dynomotion Suggestion

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    .....

    I finally got everything connected in a working PC case (Enclosure) . I am now ready to start testing the X-Axis with the rotary axis encoder connected to the back-side of the stepper motor.

    However, I am not sure on what I should be using on "I" Gain for the initial PID ("I" Gain ) setting for testing in the "Step Response" screen on my testing.

    I have a few question:

    REF.: 4000 * 4 * (1000/60) = 267K Counts/Sec.

    1.) When dealing with rotary and/or linear encoders, is the Cycles/Rev. the Same as the Step/Rev?.

    2.) Is my math correct? If I have a rotary Encoder that has a 4000 cycles/Rev. = 4000 Cycles/Rev. * 20 Rev. /IN = 80,000 Cycles / IN?

    3.) If this is correct, then (80,000 Cycles/IN) / (64,000 Steps/ IN) = 1.25, which will = the Input "I" Gain on KFLOP "Step Response" screen. I should be using this "I" Gain for testing my X-Axis with a Rotary Axis on the stepper motor on the initial tuning.

    ...
    Taig CNC Machine Quick Links
    ....
    ....

    KFLOP Power Suppy

    Stepper Motor Power Supply Used

    Stepper Motor Used on Taig

    Taig CNC Machine Counter Weight Design

    Taig CNC Machine Counter Weight Design - 3D STEP File

    Word Doc. of my Calculation for the Trajectory Planner

    Word Doc. E6 Optical Kit Encoder

    Relay Connection to KFLOP JP6 Pin 16 (I/O 35)

    E6 Encoder PinOut to KFLOP PinOut


    ....
    ....

    Last edited by PeterTheWolf; 01-27-2020 at 07:24 PM. Reason: Spelling


  10. #50
    Member TomKerekes's Avatar
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    Default Re: Taig CNC-Controller Replacement-Dynomotion Suggestion

    Hi Peter,

    I am not sure on what I should be using on "I" Gain for the initial PID ("I" Gain ) setting for testing in the "Step Response" screen on my testing.
    Start with a small number such as 0.0001 to observe gradual corrections.


    1.) When dealing with rotary and/or linear encoders, is the Cycles/Rev. the Same as the Step/Rev?.
    I don't understand what you are asking. Rotary encoders have quadrature counts per rev. Linear encoders have quadrature counts per inch.


    2.) Is my math correct? If I have a rotary Encoder that has a 4000 cycles/Rev. = 4000 Cycles/Rev. * 20 Rev. /IN = 80,000 Cycles / IN?
    I believe that is correct. But we are normally interested in quadrature counts not cycles. So that would be X 4 or 320,000 counts/inch.


    3.) If this is correct, then (80,000 Cycles/IN) / (64,000 Steps/ IN) = 1.25, which will = the Input "I" Gain on KFLOP "Step Response" screen. I should be using this "I" Gain for testing my X-Axis with a Rotary Axis on the stepper motor on the initial tuning.
    Assuming 320,000 encoder counts/inch and 64,000 steps/inch then the InputGain should be 64000/320000 = 0.2 to have them count at the same rate.

    Note I believe you are confusing Integrator gain ('I' gain) on the Step response screen with InputGain on the Configuration Screen. They are different things. The first just scales the encoder reading. The latter controls how fast errors are attempted to be corrected. You might read this.

    HTH

    Regards
    TK http://dynomotion.com


  11. #51
    Member PeterTheWolf's Avatar
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    Default Re: Taig CNC-Controller Replacement-Dynomotion Suggestion

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    ...
    .......

    Tom,

    I have the rotatory Encoder connected to the back of the stepper motor's shaft and I am trying to tune the one Axis (X-Axis Motor) on the bench without a load.

    However, I am experience issues once again. I always get confused on this part of using KFLOP.

    Here are the screen images of my settings:

    Taig CNC-Controller Replacement-Dynomotion Suggestion-001_test001-jpg

    Taig CNC-Controller Replacement-Dynomotion Suggestion-002_test001-jpg

    Taig CNC-Controller Replacement-Dynomotion Suggestion-003_test001-jpg

    Taig CNC-Controller Replacement-Dynomotion Suggestion-004_test001-jpg

    Can I please get some more advice on the direction I need to go to correct what is happening?

    What I am seeing on the motor is the motor making the move and at the end of the move it seem like it is hurting for a final position. I have to tick off the I/O State #45 to shut it down.

    ...
    Taig CNC Machine Quick Links
    ....
    ....

    KFLOP Power Suppy

    Stepper Motor Power Supply Used

    Stepper Motor Used on Taig

    Taig CNC Machine Counter Weight Design

    Taig CNC Machine Counter Weight Design - 3D STEP File

    Word Doc. of my Calculation for the Trajectory Planner

    Word Doc. E6 Optical Kit Encoder

    Relay Connection to KFLOP JP6 Pin 16 (I/O 35)

    E6 Encoder PinOut to KFLOP PinOut



  12. #52
    Member TomKerekes's Avatar
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    Default Re: Taig CNC-Controller Replacement-Dynomotion Suggestion

    Hi Peter,

    That looks like the hardware is working correctly. Servo hunting/dither is normal as the feedback keeps trying to drive the error to zero. You might read this article. In the future post the data file so we can re-plot the data as necessary.

    Regards
    TK http://dynomotion.com


  13. #53
    Member PeterTheWolf's Avatar
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    Default Re: Taig CNC-Controller Replacement-Dynomotion Suggestion

    Quote Originally Posted by TomKerekes View Post
    Hi Peter,

    That looks like the hardware is working correctly. Servo hunting/dither is normal as the feedback keeps trying to drive the error to zero. You might read this article. In the future post the data file so we can re-plot the data as necessary.
    Tom,

    I have read the information on Servo Dither/Hunting & Dead Band Tuning Parameters as suggested.

    Can I please get abit more clarity on the Dead Band and the use of it and what I may see once I get this stepper motor attached to the CNC machine?

    I have made a video of my testing with this Dead Band and I have saved the Response Data files for your review.

    The video can be download here (29,2mb.) This file can be view with the Free Media Player VLC Media Player. This file format keep the best resolution and the smallest size.


    You can download the Response Data File Here: I have made six test at different size steps trying to understand the use of the Dead Band parameters.

    Thanks,

    ...
    Taig CNC Machine Quick Links
    ....
    ....

    KFLOP Power Suppy

    Stepper Motor Power Supply Used

    Stepper Motor Used on Taig

    Taig CNC Machine Counter Weight Design

    Taig CNC Machine Counter Weight Design - 3D STEP File

    Word Doc. of my Calculation for the Trajectory Planner

    Word Doc. E6 Optical Kit Encoder

    Relay Connection to KFLOP JP6 Pin 16 (I/O 35)

    E6 Encoder PinOut to KFLOP PinOut


    ....
    ....



  14. #54
    Member TomKerekes's Avatar
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    Default Re: Taig CNC-Controller Replacement-Dynomotion Suggestion

    Hi Peter,

    Can I please get abit more clarity on the Dead Band and the use of it and what I may see once I get this stepper motor attached to the CNC machine?
    Its actually better to not use Dead Band because it basically adds backlash/slop to your system. With range of 1.8 and gain of 0.0001 it basically adds 1.8 steps of error to the system. Once the error becomes less than 1.8 steps the servo basically says, "ok that's good enough stop making any more corrections.". It should only be used if the dither around zero error is annoying for you and you are willing to allow some small error to avoid it. The type of dither you get when stopped is highly dependent on Tuning, Load, Friction, etc. so it probably isn't worth spending a lot of time on it at this point.

    On a side note you should realize where the axis is commanded can make a difference on the type of dither. The encoder only reads integer counts. Or because of the Input Gain of 0.2 Positon reads multiples of 0.2 Steps. If the axis happens to be commanded to an exact multiple of 0.2 steps (like 0 or 50000.0) then it is possible to have exactly zero error. In this case if there is enough friction, no disturbances and such the axis might sit still with zero error and need no corrections and be happy. However if commanded to some random non-multiple of 0.2 such as 123.05, then without any Dead Band it is impossible to not dither because the position will either be 123.0 or 123.2. In fact the servo will dither in a manner to spend 25% of the time at 123.2 and 75% of the time as 123.0 so the average position will be 123.05. For this reason when I'm looking at dither I intentionally move to some non-multiple position.

    The size of the move shouldn't really have any effect on the dither after the axis stops. Other than that after a big move the machine/motor might be rocking in a manner to excite some dither.

    Note that your I gain is very low (0.0001). So error corrections are being made so gradually and slow that they have a very minimal effect if any during your moves. For example in your quick move of 500 steps the green error correction plot is only showing a correction of ~ 0.05 steps. It basically takes at least 1 motor step to make some difference.


    HTH

    Regards
    TK http://dynomotion.com


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