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  1. #37
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    Default Re: servo madness

    as far as the direction goes this is what is

    when i pulled the gantry , which has 2 servos attached ch0 and ch1 both axis moved in the same direction.
    when I ran the motor in console with dac 200 for both they both went clockwise which put ch 0 movint toward and ch 1 away. I trired to work with the driver but was unable to reverse the servo so I switched the output wires on the driver.



  2. #38
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    Default Re: servo madness

    You are missing a lot of what's being said. I think going by the amount of posts your trying hard. You should probably stop testing the motor for now. You instead need to use the help files in kmotion as a library. When someone suggests you change specific settings in certain ways your pictures show you are not doing so. I feel that's because you don't really understand the terminology so your skipping those suggestions. I was the same way when I started doing these types of things. A little reading of the first section of the help file in kmotion labeled kmotion/kflop executive software screens will save you a lot of headaches getting started.

    As for changing the gains on the configuration and flash screen. I noticed that in different photos you have different values on the gains. Presently you have output channel 0 set to .5. In a different picture you had channel 0 input gain set at 2. Now it is 1. The input channel gain and output channel gain can be positive or negative 1. Do not use any other values. Doing so I believe would cause a major issues between axis.

    Ben

    Sent from my E6810 using Tapatalk



  3. #39
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    Default Re: servo madness

    servo madness-ch0-9-jpg



  4. #40
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    Default Re: servo madness

    Couple things that stand out, set the Feed Forward values to zero for now. Feed Forward should only be used to home in on a final tuning (they essentially try and predict what the axis is going to do, and although they will appear to give you a better tune and mask a poor tune, it can give you problems).

    As both your encoders do count the same way, they're fine. Leave your input gain at 1.
    As long as the drive can handle the +/-10V wires being reversed, it'll be fine now. The easier way would of been to set the output gain to -1.

    With that done, and with your motors still uncoupled, concentrate on a single channel/motor.
    Gradually start increasing P (0.5 at a time should be pretty safe), then do a Move (500 is a good starting point). What you're looking for is the difference between the command and position, and how stable/smooth the output and position is.
    Keep increasing the P and doing Moves until you notice oscillation on the output, at which point start increasing D (you can probably increase this by 1 at a time).

    Keep repeating the above, until you reach the point at which you can't get the value any higher without causing the output to oscillate.

    Then add in a bit I. Start with 0.001 increases, and if it's not doing much after a couple increase, jump to 0.01. Depending on the system, a little bit I can cause things to go unstable very quickly, whereas other systems will need quite a bit I to go unstable.
    Once things start to go unstable, lower P and D to regain stability.

    Only do this a couple times, as you're only aiming for a basic tune to ensure you've got reasonable stability at this point.

    Once that's done, increase your Maximum Output Limit to 2047, the run another 500 move to ensure things are still stable.
    Now you want to start finding the limits of the system, so start increasing the move size.
    It's probably worth doing some maths at this point to establish what you want your maximum motor speed to be, as there's not really any point tuning the motor above a speed they're ever going to run.

    Once you've established your maximum motor speed, and adjusted the tuning if needed by repeating the above, copy all the settings across to the second motor, and do some moves to ensure it's response is the same.

    Now I need to Tom to clarify how the KFlop handles slaved axes at this point. If they're slaved, does the slaved axis follow the master axis when using the Step Response screen?
    If the slaving remains active, I'd say couple the motors up, and then work towards a final tune.



  5. #41
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    Default Re: servo madness

    my final attempt for the day, I cant get the graph to zoom out

    servo madness-ch0-10-jpg



  6. #42
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    Default Re: servo madness

    That is going the correct direction, but obviously still needs work.

    What you have there, is the output rises and hits it's limit (P * max output = 100), with the actual position lagging behind the commanded position. Although you can't see the rest of the plot, what you can see is enough to work with.

    Increase J(erk) up to 4000000, as it's extremely low. Jerk is how quickly acceleration is applied, and is visible in your last plot, as the initial curve in each plot, before things hit peak acceleration (where the plots increase is essentially a straight line).


    Then do as I mentioned in my previous post about continually increasing P and D, then adding a little bit I.



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    Default Re: servo madness

    servo madness-ch0-11-jpg



  8. #44
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    Default Re: servo madness

    servo madness-ch0-12-jpg



  9. #45
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    Default Re: servo madness

    Hi jensenjim,

    Please post the IIR Filters Screen for this Axis.

    Regards
    TK http://dynomotion.com


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    Default Re: servo madness

    servo madness-ch0-13-jpg



  11. #47
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    Default Re: servo madness

    Hi jensonjim,

    Ok filters are all clear. I'm at a loss at how you reversed the drive direction without setting the Output Gain to -1 as we requested. I suppose you changed something without telling us.

    Anyway, the next step would be to add a 2nd order low pass filter and increase the D Gain to something like 10 or higher. A D value of 0.001 will be no different than none at all. Please read this article on Acceleration mode servos like yours carefully.

    Please remove Deadband by setting range to 0 and gain 1.

    Regards
    TK http://dynomotion.com


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    Default Re: servo madness

    Now you're making progress.

    Quote Originally Posted by TomKerekes View Post
    Hi jensonjim,

    Ok filters are all clear. I'm at a loss at how you reversed the drive direction without setting the Output Gain to -1 as we requested. I suppose you changed something without telling us.
    Reply #37, Jim swapped the output wires from the Drive.



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