Super slow velocity issues....

I am having issues with my Y-axis homing using AXIS but not my X-axis homing. The issue is that once it hits the Y-axis limit switch and starts to very slowly step out of the limit, AXIS thinks its moving but there is no actual movement. I've traced it back to the Y-axis cannot make very slow movements (below ~2in/min). The X-axis can make slower movements. Is there a variable that controls the minimum velocity or does this sound like stepper driver issues? Any suggestions on where to look would be appreciated. Thanks

In the ini file under the joint 1 for Y axis there are several enties for homing, below the home_search_velocity is the one you should change named home_latch_velocity.
By default it is set very low.
Is there any particular reason why Y axis will not move at lower speeds ? That is not how it should be, on all the machines i can move any axis at an extreemly low speed.

Thanks for the response. I'm aware of the home_latch_velocity and I increased that as a stop-gap measure.

There is no reason that I am aware of why the Y axis should not move at lower speeds. I was hoping someone has some ideas.

I forgot to mention the following hardware in my original post:
-1.8deg stepper (x10 microstepping)
-Mesa 5i25/7i76
-Gecko 202 stepper driver

Thanks

I saw a post recently from PCW where he said the Gecko 540 struggles at low velocities and your stepper is a very close relative..... try increasing the step length >5,000 was something he said...

I contacted Gecko about this issue and they said it didn't sound right and to send back the drive for evaluation. I sent the drive back but they indicated "no problem found". It still exhibits this behavior.

Anyone else have any ideas on what might be causing this? (again I'm using Mesa 5i25/7i76)

RodW - can you elaborate on how/where to change the step length? I didn't see anything that look like it in my .ini file. I fear editing with the Config wizard again because I have custom tweaks to my hal and ini files I don't want to risk.

I wanted to do one last attempt at fixing before buying a new stepper drive that may or may not fix the issue.

Thanks.

[quote="nigel-tufnel" post=93244}

RodW - can you elaborate on how/where to change the step length? I didn't see anything that look like it in my .ini file. I fear editing with the Config wizard again because I have custom tweaks to my hal and ini files I don't want to risk.

Thanks.[/quote]


In your ini file under each joint but mine will be waaay tooo short.

But review this

linuxcnc.org/docs/2.7/html/motion/tweaking-steppers.html