Understanding Backlash concept in initialization file

[AmitKumar171]

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.

[TomKerekes]

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

[AmitKumar171]

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.

[TomKerekes]

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.