Understanding Backlash concept in initialization file

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AmitKumar171
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Joined: Tue Feb 20, 2018 7:35 am
Location: India
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Understanding Backlash concept in initialization file

Post by AmitKumar171 » Wed Nov 27, 2019 11:43 am

Hi tom ,

I am using init program for kflop all axes there is some amount of ballscrew backlash is there.

How to adjust it in init file. ?

and here is a portion of init file that is having backlash options.

ch0->InputMode=NO_INPUT_MODE;
ch0->OutputMode=STEP_DIR_MODE;
ch0->Vel=10667;
ch0->Accel=260000;
ch0->Jerk=1e+06;
ch0->P=1;
ch0->I=0;
ch0->D=0;
ch0->FFAccel=0;
ch0->FFVel=0;
ch0->MaxI=200;
ch0->MaxErr=1e+06;
ch0->MaxOutput=200;
ch0->DeadBandGain=1;
ch0->DeadBandRange=0;
ch0->InputChan0=0;
ch0->InputChan1=0;
ch0->OutputChan0=0;
ch0->OutputChan1=0;
ch0->MasterAxis=-1;
ch0->LimitSwitchOptions=0x100;
ch0->LimitSwitchNegBit=0;
ch0->LimitSwitchPosBit=0;
ch0->SoftLimitPos=1e+09;
ch0->SoftLimitNeg=-1e+09;
ch0->InputGain0=1;
ch0->InputGain1=1;
ch0->InputOffset0=0;
ch0->InputOffset1=0;
ch0->OutputGain=1;
ch0->OutputOffset=0;
ch0->SlaveGain=1;
ch0->BacklashMode=BACKLASH_OFF;
ch0->BacklashAmount=0;
ch0->BacklashRate=0;

ch0->invDistPerCycle=1;
ch0->Lead=0;
ch0->MaxFollowingError=10000000;
ch0->StepperAmplitude=20;

in above lines what is the units of backlash amount and backlash rate.? , and if i have a backlash of 0.01mm in each axis then what will be the unit of backlash amount and backlash rate. If my counts per inch for each axes is 8128. Then how to calculate backlash amount and backlash rate. ?

Waiting for your kind reply.
Thank You

AMIT KUMAR

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TomKerekes
Posts: 665
Joined: Mon Dec 04, 2017 1:49 am

Re: Understanding Backlash concept in initialization file

Post by TomKerekes » Wed Nov 27, 2019 3:05 pm

Hi Amit,
what is the units of backlash amount and backlash rate.?
steps and steps/second

Amount = 0.01 x 8128 / 25.4 = 3.2
Rate to move in 0.01 seconds = 3.2 / 0.01 = 320
Regards,

Tom Kerekes
Dynomotion, Inc.

AmitKumar171
Posts: 55
Joined: Tue Feb 20, 2018 7:35 am
Location: India
Contact:

Re: Understanding Backlash concept in initialization file

Post by AmitKumar171 » Thu Nov 28, 2019 4:58 am

Hi tom,

Thanks for your reply.
steps and steps/second

Amount = 0.01 x 8128 / 25.4 = 3.2
Rate to move in 0.01 seconds = 3.2 / 0.01 = 320
Ok i got it, but what if i make this rate to a huge value 24000, then what will happen. ?

Waiting for your kind reply.
Thank You

AMIT KUMAR

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TomKerekes
Posts: 665
Joined: Mon Dec 04, 2017 1:49 am

Re: Understanding Backlash concept in initialization file

Post by TomKerekes » Thu Nov 28, 2019 9:45 am

Hi Amit,

Then the 3 step pulses will be made very fast. In 3.2/24000 = 133us. This is basically instantaneously from a Stepper motor’s perspective.
Regards,

Tom Kerekes
Dynomotion, Inc.

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