Reversing direction causes motors to jerk

I've tried everything from 2 micro steps up to 16.

Power supply voltage?

Ok, hold everything for a while. From your original post, you have a gantry machine with 4 motors. please confirm. It looks like you must be using v 2.7.

Its strongly recommended that you upgrade to Master branch (V2.9) or V2.8.
This will give you the ability to run s seperate joint for all 4 motors. So it will mean you will be using a seperate 7i76 stepgen for each side of the gantry with seperate stepper controllers for each motor.

You will also need to install home switches on each side of the gantry. This will let Linuxcnc square the gantry on homing. The homing is quite different under 2.8/2.9 See linuxcnc.org/docs/devel/html/config/ini-homing.html

Run Pncconf again (it will probably have a few more features) reconfigure your machine again and report back.

Leon82 wrote:

Power supply voltage?

x2 what voltage are you running your steppers at?

Leon82: Power supply voltage is 48

rodw: Will do. It'll take me a bit, but I'll report back once I'm done.

I agree the 2.8 is better for gantry machines,
_but_ I really doubt that it will change your
reversing issue, so I think it would be better to understand/solve
that issue first before adding more variables...

Some of the Chinese supplies won't put out their rates voltage under load. With 4 34 steppers you may be dropping. My 60 volt wouldn't go over 42 with 2 23 and a 34 on it.(while idle)

I'm using the Avid power supply with their motors, so I assume that's not the problem. I have measured the voltage at the Geckos between 46-48 depending on load. This also happens when I only have a single motor hooked up.

Is it possible you are going into step drive standby at reversals?
You might try disabling this feature (set the standby current to 100%)

Just tried disabling standby and it didn't help. Good idea though.