Intermittend stepper hickup after cold start

Hi,
I just started testing my CNC-mill Z-axis with a NEMA23 on a DuetWifi.
I noticed that within one hour of testing the stepper didn't properly respond twice on the first G1 command.
As a basic test, I didn't home the axis, but sent G92 Z0, followed by G1 F400 Z10

Two times, right after switching the PSU on and establishing Web-control the above mentioned procedure ended in a squeaking stepper that doesn't move.
Without changing anything, I repeated the G1 command and it worked flawlessly.

My parameters:
Max feedrate : 400mm/min ( lead screw is the limiting factor here )
2560 steps/mm
Acceleration 1000mm/s²
Jerk 120mm/min
Current 1.8A for a 2.1A stepper @24V
RRF 1.18

Is it necessary to initialize the drivers before the first move command ?
Eg.

G90
G92 Z0
G1 F400 Z0 ( stepper would not move but driver got energized )

BTW: the NEMA23 is surprisingly quiet with the 16/256 interpolation

Edited 2 time(s). Last edit at 06/13/2017 02:21PM by o_lampe.

Your Z acceleration of 1000mm/sec is way too high for a steps/mm of 2560. Try 100 or lower. The jerk is also rather high.

Edited 1 time(s). Last edit at 06/13/2017 03:07PM by dc42.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Testing goes on today with a +5kg weight on the z-axis. I'll try your values and report.
Thanks dc42