Axis compensation M556

[jian118]

1) When i issue M556 i get no response. 2) When i put in M556 S74.5 X-0.5 Y-1.5 Z-0.5 in the config or sending the code through Ormerod Control, with the Ormerod2's Home-Z button pressed, it start going up none stop.

Firmware: 0.78b & 0.78c Could anyone advise?

[RRP-support]

1) Sending M556 on it's own won't give a response. See http://reprap.org/wiki/G-code#M556:_Axis_compensation for usage. Feedback has been added to the command, so that sending M556 on it's own does give the current setting, but in a later firmware commit. To reset M556, send M556 S100 X0 Y0 Z0. 2) It's a bug, which we need to look at. If you send M556 with the axes homed, ie when the nozzle is at X0, Y0, Z0, then ask for the Z axis to go up, with your setting it causes the X and Y axis to go negative (and probably triggers the endstop). This causes the firmware to get stuck. To avoid this, move each axis away from zero, eg to X5 Y5 Z5, before homing, though it may still cause problems. Also Y-1.5 is a lot of compensation; consider trying to get your printer straighter mechanically first. Ian RepRapPro tech support

[jian118]

Thanks for the reply. I didnt notice the screw used to perform the calculation is coarse screw as it is not included in the kit(for the new kits please do include one for others). I used the remaining fine thread screw which made the calculation differ so much. Besides that, the manual bed axis compensation I found in Omerod1 documentation is very useful. Consider including them in Ormerod2 documentation. And the motor mount for x axis is not thick enough causing tension to the belt. I added one m3 nut on each side between the mount and motor to give further space and it solved the problem. Dont know whether it happens to others. Anyway, well done with the product.

[RRP-support]

The issues system in github is for raising specific RepRapFirmware bugs. Please email support@reprappro.com for more general support. However, thanks for your comments. To answer these: All the M3 screws are the same pitch, we don't have any coarse-thread M3 screws. The gradations on the dial are actually 0.05mm; a whole turn is 0.5mm, which is the pitch of the M3 screw. You can use a spare M3x20mm cap head screw with a nut on the back, and there's no need for a spring. We need to change the instructions, as, as you point out, we don't include these items in the kit. With recent firmware updates, the automatic bed calibration works well, and is easier than the manual calibration. It also has the advantage of coping with the bed moving day-to-day, and if you do it when the bed is at working temperature, it also takes account of bed movement due to heat expansion. You may find that it would be easier to move the pulley (check it's on the right way around) on the x-motor shaft to get the belt running smoothly, rather than have nuts between the motor and the x-motor-mount; the axis relies on the motor to provide some clamping force, to hold the x-axis smooth rod. I hope that helps. Ian RepRapPro tech support

[RRP-support]

Also, feel free to close this issue if your problem is resolved! Ian RepRapPro tech support