I think the stepper drivers are shutting down when I home the Z axis.
I have a Mendel90 which has two NEMA17 steppers (x16 microstepping) in series (E.g. to one single connection on the 'cape) for the Z axis. The fabulous folks on the IRC channel tactfully pointed out I had a too low current to drive two z motors, and a much too high speed. Having sorted that out, homing Z seemed to work.
Now however I’m trying to get ‘0’ to mean the bed, so set home_z = -0.190 - hoping that would be roughly 1cm off the bed (E.g 1cm less than the roughly 20cm build height), so I could measure it more precisely.
Here’s what happens:
- The z-axis moves up towards my z endstop
- Hits the end stop then pulls back
- Moves back up to the end stop (usually this is slower, but I’m already going slow)
- Then starts moving down towards the bed (as I wanted). However, it only moves about 6cm before stopping, and Octoprint just stops responding. I see no Redeem errors in /var/log/syslog. Without restarting redeem or octoprint, it does after a few minutes begin responding again.
The z driver is very hot to the touch, so wondering if this is what’s happening? Certainly the steps/mm for z is right (Easy with an M6 rod - 1mm pitch, 200 rotations).
Question is what do I do? I’ve taken the current down to 1.0 (remember that’s for two motors), and when it was too low, one of them didn’t turn, causing the other to attempt to bend the x-carriage!
Here’s my full config:
[System]
[Geometry]
Cartesian XY
axis_config = 0
Set the total length each axis can travel [meters]
travel_x = 0.20
travel_y = 0.20
travel_z = 0.20
Define the origin in relation to the endstops [meters]
offset_x = 0.00
offset_y = 0.00
offset_z = 0.00
Stepper e is ext 1, h is ext 2 [In powers of 2, so ‘4’ is 2^4 = 16]
[Steppers]
microstepping_x = 4
microstepping_y = 4
microstepping_z = 4
microstepping_e = 4
Drivers are rather 1.5 max. Z needs more as two in series.
current_x = 0.5
current_y = 0.5
current_z = 1.0
current_e = 0.6
steps_pr_mm_x = 4
steps_pr_mm_y = 4
steps_pr_mm_z = 200
steps_pr_mm_e = 33.4
Only one extruder
in_use_h = False
[Heaters]
Epcos 100 K
temp_chart_E = B57560G104F
Epcos 100 K
temp_chart_HBP = B57560G104F
[Endstops]
end_stop_X1_stops = x_ccw
Normally you’d use Y1 - but seems to be broken on mine
end_stop_Y2_stops = y_ccw
end_stop_Z1_stops = z_ccw
[Homing]
Homing speed for the steppers in m/s
home_speed_x = -0.02
home_speed_y = -0.02
home_speed_z = -0.001
home_speed_e = 0.02
home_x = -0.10
home_y = -0.10
home_z = -0.190
[Planner]
Max speed for the steppers in m/s
max_speed_x = 0.1
max_speed_y = 0.1
max_speed_z = 0.001
max_speed_e = 0.1
In fact, that exact section!