Dynomotion

Group: DynoMotion Message: 6491 From: jrccyah Date: 1/16/2013
Subject: Lost Steps Any Step Motor
For sure I'm doing something wrong.

I am using my new KFlop+KStep with open loop step motor and KMotion SW 4.29 and I found some strange behavior, so I decided to simplify things to make an experiment. Straight to the point:

a) I attached a small pointer to the shaft of a lonely Stepping Motor in order to have a reference.

b) Using KMotion Step Response Screen (using Step Size = 1000) pressing "Move" button a couple of times the pointer do not return to initial position. More you press bigger is the error .

c) Changing acceleration, velocity, motor nothing change, i.e. you get the error is still there.

d) Changing Step Size to -1000 instead of 1000 the movement is reversed, but the error increments to the same side as before.

Can anyone help me?
José Roberto
Group: DynoMotion Message: 6498 From: Tom Kerekes Date: 1/16/2013
Subject: Re: Lost Steps Any Step Motor
Hi José,

The Step/Dir Generators in the FPGA need to be configured for large inverted pules with a C Program statement:

    FPGA(STEP_PULSE_LENGTH_ADD) = 63 + 0x80;  // set polarity and pulse length to 4us

Otherwise it is possible to get a step in the wrong direction when the direction reverses.

Have you executed this?  It is included in the InitKStep3Axis.c example.

Regards
TK