So, when doing calibration i found it a real headache because after a move, the motors shut off and would revert to their last full step, which is a bout 1-2mm of movement in the gantry. Jog 100mm, it moves 101mm and snaps back to 99.4 and just causes a headache when trying to calibrate it all, until I discovered this setting today: "$1 - Step idle delay, msec Every time your steppers complete a motion and come to a stop, Grbl will delay disabling the steppers by this value. OR, you can always keep your axes enabled (powered so as to hold position) by setting this value to the maximum 255 milliseconds. Again, just to repeat, you can keep all axes always enabled by setting $1=255. The stepper idle lock time is the time length Grbl will keep the steppers locked before disabling. Depending on the system, you can set this to zero and disable it. On others, you may need 25-50 milliseconds to make sure your axes come to a complete stop before disabling. This is to help account for machine motors that do not like to be left on for long periods of time without doing something. Also, keep in mind that some stepper drivers don't remember which micro step they stopped on, so when you re-enable, you may witness some 'lost' steps due to this. In this case, just keep your steppers enabled via $1=255." The question is, are the motors from the store ok with being constantly powered? There is a slight hum of power going through them, and today I just reverted $1 back to 50 after I calibrated (because when running a program they stay on anyways) but it'd be nice if I didn't have to switch back and forth! Cheers
do not disable the motors, ie set $1=255. they will always lose absolute position if you do, unless you set microstepping to '1', which is not practical. fancier stepper drivers (big $) remember exactly which step they were on and go back there when re-enabled, but the stuff we use does not and the magnets jump to the nearest whole step when disabled. when constantly powered, the motors and possibly drivers will get hot, but no hotter than if they were cutting an hour long job. if you have to spend an hour working on a drawing or having tea, then turn the machine off.
I don't know why this is not a bigger issue. I keep $1=255 to avoid losing steps but I can easily forget to shut down my system and the next day find the steppers powered all night. It's a waste of electricity and not good overall. I wish there was a way to set idle time beyond 254 - like a couple of hours or so - or a separate setting. If someone knows how to modify the GRBL library C code for this, please advise. Another wish is to fix keyboard arrow jogging - the arrows should not change the rate slider bars - apparently the code is confused about what part of the UI has focus.
