That 0.5 uS spec is for the minimum time the clock needs to be low. STEPLEN is the time to remain high. You have STEPSPACE=0 which means the low time is to be "0 nanoseconds". I'd make STEPSPACE much larger.
BTW, that L297 is primitive at best. You'd be amazed at how much better the new stepper drivers are and the price has come down. You get much better performance (more speed and torque) and no high-pitched noise. Something like one of these on each axis would be a great upgrade. Buy a 24V or 35V power supply to go with it. .omc-stepperonline.com/digital-stepper-driver/digital-stepper-driver-18~56a-20-50vdc-for-nema-23-24-34-stepper-motor-dm556t.html <https://www.omc-stepperonline.com/digital-stepper-driver/digital-stepper-driver-18~56a-20-50vdc-for-nema-23-24-34-stepper-motor-dm556t.html> On Wed, Jun 2, 2021 at 5:48 AM Fox Mulder <[email protected]> wrote: > Hi, > > i try to reactivate my old self-build cnc mill with stepper motors and > come to a little problem. My 15 year old electronics seems all still to > work. It uses L297/L298 stepper drivers driven by the parallel port from > my old pc which is quite outdated but this doesn't matter at the moment. > > I reinstalled Debian with LinuxCNC v2.8.1 and at first start it updated > my old config files. But then when i try to jog one of my axes it > doesn't work. I only get some jitter from the motors but no movement. > > After some investigation i found out that the width of the step pulses > is too small. At the moment they are ~2,3µs which should be valid > because the datasheet of the L297 says a minimum of 0,5µs is ok. But > when i try the step generation with a simple python script which has a > wider step pulse the motors move how they should. So i think i can get > it to work again with a wider pulse. > > Now to my question, how to make the pulse width for the step signal > wider. I read in the stepgen module about the steplen parameter but it > seems i'm not setting it correct. > > In my old hal file the configuration for the stepgen module looks like > this: > > loadrt stepgen step_type=0,0,0 > addf stepgen.make-pulses base-thread > addf stepgen.capture-position servo-thread > addf stepgen.update-freq servo-thread > > setp stepgen.0.position-scale [JOINT_0]SCALE > setp stepgen.0.steplen 1 > setp stepgen.0.stepspace 0 > setp stepgen.0.dirhold 51056 > setp stepgen.0.dirsetup 21056 > setp stepgen.0.maxaccel [JOINT_0]STEPGEN_MAXACCEL > > Now i tried to increase steplen to something like 10000 and expected a > step pulse width of ~10µs but nothing changes. The pulse width is still > ~2,3µs. > > Is there something i'm missing or what is the best way to change the > pulse width of the generated step signal? > > Ciao, > Rainer > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
