Z axis falls

I just got my Kflop/Kstep running in open loop using Kmotioncnc. I'm using C:\KMotion431\C Programs\KStep\InitKStep3Axis.c for my c program. When I let the machine sit idle the spindle will move down about .100 but it doesnt show the movement on the green DRO. I installed encoders and they show that the motor is turning, so i dont think it is backlash or mechanical issue causing the move. If I turn off the stepper motor power supply I dont experience the problem. I wonder if it has to do with the amplifier being turned off when it sits idle?

Hi 09FLHX,

The example InitKStep3Axis.c has the code shown below to loop watching for no motion for 10 seconds to disable KSTEP. You can observe on the KMotion Digital IO Screen IO 45 to see when KSTEP is enabled.

That might be what is causing Z to fall. Try removing this code to see if it helps.

Regards
TK

Code:

---

        for (;;) // loop forever
        {
                WaitNextTimeSlice();
               
                // Service Amplifier disable after no activity for a while
                if (ch0->Dest != LastX || ch1->Dest != LastY || ch2->Dest != LastZ)
                {
                        // we moved - enable KStep Amplifers
                        SetBit(45);
                        T0 = Time_sec();  // record the time and position of last motion
                        LastX=ch0->Dest;
                        LastY=ch1->Dest;
                        LastZ=ch2->Dest;
                }
                else
                {
                        if (Time_sec() > T0 + 10.0) ClearBit(45);
                }
        }

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