LitePlacer.com forums

Hello,

we have a problem with our liteplacer at calibration and sometimes at moving: The A axis spins endlessly!
This was working before, but when we did some additional configuration the software crashed unexpectedly and afterwards all values were different, so we had to key in everything again... But now we have the rotation bug and don't know how to correct it.

Another issue which is eventually related - sometimes the software asks to "home now" while the machine is idle!?

Here is a little video of the spinning axis: https://www.youtube.com/watch?v=-x14Jfdu6Lc

Somehow, the TinyG internal settings got corrupted, and seems like it reset to defaults. The A axis issue is aam parameter. (It will stop eventually, but it has radians and degrees mixed now). The home now issue is the motor timeout value. the default is 2s, when 5min is more sensible. The software reads the timeout value and knows, when TinyG switches off motor power. That makes the machine loose accurate position, so homing is needed.

Since you have put in most of your parameters already, here is how to put in the rest. Send text $$ to TinyG; that will dump all the settings in human readable form to the log window. For reference, find the link to "Example of expected startup message and a settings dump" on the downloads page. The end has a dump with good settings. Compare my dump to yours; the velocity, feedrate and jerk values are machine dependent, as you already know. For values that are different, the command format to set better values is:

$aam=1
$mt=300

And if there are other differences, do those as well.

Thanks JuKu,

this solved the problem! We were not aware that relevant parameters would not be shown in the software.
Regarding Homing: So we could set the motors to always-on until we finished all calibrations and such?

Some parameters are set once and forget -nature. Those are written by the set defaults function and not shown in the user interface. Looking back now, it would be better ways to do that. I instructed you the way I did because you said you had some calibrations done; I hope that way was easier than redoing the calibrations.

For motor power, you should use option 2 "in cycle": This keeps all motors powered until the mt parameter timeout. The motors actually use most power when they are not moving but just holding position. In my opinion, it makes sense to cut power if you are not using the machine for awhile. Although the machine looses position and you need to rehome (the software knows the timeout value and asks for the rehoming), you are not overstressing anything.