I’m trying to troubleshoot some minor deviations in my X axis. Tightening up pulleys and belts and V-wheels seems to have dealt with the issue, but it got me thinking— with the idle current reduction in the X-Controller, if I’m carving a long line that’s perpendicular to an axis, that axis will have reduced torque but will still be experiencing full load.
For example, consider carving a long, straight line from the “front” of a workpiece to the “back”, where the machine is only moving in the Y axis:
In this case, there is no movement in the X axis so, if I understand correctly, the X-Controller will reduce current to the X axis. Therefore, there will be less holding torque on the X axis, even though the carriage is experiencing load as it removes material. This would create the potential for slipping and losing steps.
I’m leaning toward completely disabling idle current reduction for this reason. Does anyone else have any input on this? Is there something incorrect in my understanding?
GRBL doesn’t disable any stepper motor unless ALL of them are idle for the step idle delay setting duration. It’s easy enough to set $1=255 if you want to double check anyway.
Some stepper drivers have a built-in thermal protection which could temporarily disable the stepper motors. I would be truly surprised if the X-Controller didn’t take this into account, but maybe double check that it has proper ventilation.
Idle current reduction in an X-Controller feature, not a grbl feature. From the documentation:
Idle current reduction is another feature that can be set on the controller board. This setting automatically reduces the amount of current shortly after the motor stops moving, reducing heat from the driver and the motor. This feature is especially great for the Z axis which spends a lot of its time idle. You can set this using the dip switches, just make sure to again check out the diagram for proper placement.
Let’s face it, we’re all pushing our machines more than a normal/average user would.
A normal user, most likely, would not have any issues with the idle current turned on while running feed rates and depths that is Easel recommended.
Now, with Inventables pushing Vcarves and multi-stage carves, the dynamics of the situation changes. The carriage slipping on bit changes will become a CS problem and the easiest solution for that is to disable idle current reduction.