Kflop + stepper motor axis drifts

[konstantinshr]

Need help. I have Kflop + driver 2MA860H + stepper motor. Moves axis 10 times back and forth for 1 mm. Result - axis drifts in the negative direction by 0.1 mm.
Reverse wires on the stepper motor axis began to drift in the positive direction.

Regards Constantin.

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[TomKerekes]

Hi Constantin,

That is often caused by insufficient Direction Setup Time. Try setting the pulse time to maximum 3.78us and try inverting the Step Pulse Polarity. See the example:

SetStepPulseLength.c

and also:

Step and Direction Setup

Regards

[konstantinshr]

I did as it is written in the manual. I added a line to the FPGA initsaalizatsiyu (STEP_PULSE_LENGTH_ADD) = 32;. But the driver did not respond. I increased the number to 39, and the driver began to move. But there is a drift in the negative direction. The problem kflop. I changed the wires on the stepper motor and drift became positive

[TomKerekes]

Hi Constantin,

The timing must be set properly for your drives.

Try the maximum value of 63.

If there is still drift then try inverting the pulse by adding 0x80

FPGA(STEP_PULSE_LENGTH_ADD) = 32 + 0x80;

Regards

[konstantinshr]

I did all this. Experimentation has shown that a maximum of 70. But the drift is not disappeared. I tried FPGA (STEP_PULSE_LENGTH_ADD) = 32 + 0x80; But the dead driver. Begin to move with FPGA (STEP_PULSE_LENGTH_ADD) = 39 + 0x80; But the drift still remains.

[TomKerekes]

Hi Constantin,,

My mistake. The maximum value is 63. Try

FPGA(STEP_PULSE_LENGTH_ADD) = 63 + 0x80;

and

FPGA(STEP_PULSE_LENGTH_ADD) = 63;

What Version of KMotion are you using?

Regards

[konstantinshr]

Hi Constantin,,

My mistake. The maximum value is 63. Try

FPGA(STEP_PULSE_LENGTH_ADD) = 63 + 0x80;

and

FPGA(STEP_PULSE_LENGTH_ADD) = 63;

What Version of KMotion are you using?

Regards

KMotion Version 4.33

[TomKerekes]

Thanks.

Did you try those two settings individually?

Regards

[konstantinshr]

Not yet. Today, I will try.

[konstantinshr]

Thanks.

Did you try those two settings individually?

Regards

Hi Tom.
Today I tried - a negative result. The drift continued.
I have 2 axes X and Y stepper motors and a Z-axis servo drive.
On the axis Z drift absent.
What else can you recommend?

Regards Constantin.

[TomKerekes]

Hi Constantin,

Are you sure you tried both of those settings correctly? Please post the two C programs you tried.

How are the Step/Dir Signals wired? How long are the cables?

How did you configure the KFLOP Axes?

What are the specifications for the Z axis Step/Dir signals?

Regards

[konstantinshr]

Hi Constantin,

Are you sure you tried both of those settings correctly? Please post the two C programs you tried.

How are the Step/Dir Signals wired? How long are the cables?

How did you configure the KFLOP Axes?

What are the specifications for the Z axis Step/Dir signals?

Regards

Hi Tom.
I have a Chinese 4-axis machine through Ncstudio. We changed management to kflop + konnect. X Y stepper drive Z A servo drive. Step / Dir Signals wired. Length 0.8 m
I changed the speed and acceleration but drift left.
I inverted the wires on the stepper motor - the result changed the direction of the drift.

Regards Constantin.

[TomKerekes]

Hi Constantin,

The Init Files are correct. I assume you ran them right before doing your test?

I was hoping you would include details of how you wired the Step/Dir signals. Did you connect +5V from KFLOP JP7 to the +DIR +Pulse signals on your drives?

Otherwise if you happen to have an oscilloscope you might verify that the Direction and pulse timing from KFLOP is correct.

I believe the drive specifications for voltage levels of the Step and Dir inputs are > 4.5V for on and less that < 0.5V for off. KFLOP meets the spec of >4.5V but only about 1.2V for off (internal protection diode to 3.3V supply limits pin to ~ 3.8V). I have never seen this to be a problem as most LEDs require at least 1.4V to turn on even without any series resistance.

You might check the voltage levels across the Drive Inputs with a Voltmeter. On KFLOP Power up the pins should be inputs "Open" and you should see 1.2V or less on the drive. Then use the Digital I/O Screen to set the Pins (Bit 8 and Bit 9) as an output and low. The voltage at the drive should then be 4.5V or more.

You might also check your +5V supply.

You might add a Line Driver module to make sure it isn't a voltage level issue. Such as:

https://cnc4pc.com/differential-line-driver.html

Regards