Lichuan 4 axis stepper need help-

Lichuan promptly (as in 'same day') responded to my request for manual and software. They're shared here:
git.gitcoding.net/nwe/lcec_4x_stepper.git

Awesome! Rony didn't come back to me.

Here is what I managed to squeeze out for velocity. It seems 10000 set 60rpm so I must have had them at 3000rpm. They were really squealing. If I bumped it up to 600000 they stalled and sat there squealing.
>halcmd: setp lcec.0.0.0-target-velocity 500000

In the process of trying this, I made an interesting observation: I knew my 24V 5A psu is too small and will lose out at some point. It tripped about 2-4 seconds after I changed the 4th motor from target-velocity 0 to target-velocity 500000. All 4 motors stalled and the drive's LED's blanked. The psu reset, the drive lit up, then a few seconds later, all 4 motors resumed full speed. This cycle continued about twice, then I stopped two motors.

I checked dmesg, sure enough, it showed ethercat had come and gone several times.

The fascinating part is the way the drive remembered its previous state after a power droop. I have this running in velocity mode. Position mode 8 would hardly be affected by the following scenario: I envision the potential of a power droop stopping the pc then moments later the servos continue in their most recent trajectory, meanwhile the pc slowly boots... I guess on machinery where this would matter, the e-stop ciruit would also release, preventing anything from moving uncontrolled.

Earlier today I disassebled this drive and discovered it appears the encoder feedback part of the pcb is fully populated except for the connectors. I will try to connect an encoder and try to activate that... see if I get counts in velocity mode.

One more observation I made while I had it apart: the pcb is conformal coated - a sure sign of decent quality!

It can be that the motor speed needs to be ramped up, like it is by linuxcnc.
Setting 6000 rpm as a step is quite challenging.
Anyway, 3000 rpm is more than decent for a stepper motor.

Consider to use csp mode, that's what most people do.
The position feedback is lagging two servo cycles when using ethercat
and a velocity loop has a hard time.

If you use csp, the position update will stop in your scenario, and the motors will stop.
Check out the SDO listing, there is a max current setting (per motor).