Lost steps/no motor movment jogging at low jog rates.

Im having intermittent problems with one axis of two on 2.7.0 and 2.7.14. usualy right at startup i can jog slowly 1mm/min-100mm/min but after a whilr one axis shows dro movmemt but no motor movment.
i had jitter or 33000 with 1gb ram. upgraded to 7gb of a ssd and got jitter to 19000. But problem remains.

Upgrading from 2.7.0 to 2.7.14 seemed to improved but the problem is still there. Ive swaped drives /motors/cables but the problem stays with one axis. also tried new configs .

drives a G540.

Anyone seen this problem before?

thanks

these were set to steplen 1
stepspace 0
dirhold 20200
dirsetup20200
on both axis
from the g540 config i think?

i changed
steplen 15000
stepspace 15000

Problems still continue but seemed better? mayne have just been becuse i restarted linuxcnc.

fixed!
I swaped to a diffrent drive from thr g540 and no problems. So must have been hardwear problem. I thought i had done this earlier.

Its got better but still dose it now when jogging 0.1-1mm/min. i keep working on the step and len settings

Replied by andypugh on topic Trying to get Mesa 5i25 to generate steps for G540
PortlandGTS wrote:
setp hm2_5i25.0.stepgen.03.steplen 1
setp hm2_5i25.0.stepgen.03.stepspace 0

PCW has already pointed out that this is the problem. But I thought I would explain what has happened.

Stepconf uses the parallel port "reset" function to create the step pulses. This is a bit of code that runs a fixed number of nS after the parallel port write, and writes 0 back to any pins with the reset flag set.
This means that the system can create a step pulse every base period, rather than every two base-periods.
In this scenario the actual step pulse length is set by the reset time, and the step space length is simply the rest of the base period time. The step length and space are set to nominal values so as not to interfere with this timing.

In the case of a FPGA card, it really can do a 1nS pulse length, but that won't operate the drive. So you need the real pulse and space lengths in those parameters.

i wonder what effect this has?