What exactly does PID tuning do?

crchisholm

I am going to put this on hold for the time being. Appreciate all the input and assistance. I have ordered the thermocouple and daughter board and will see what that brings to the game. As it stands now, I can get some pretty good prints (I've only used PLA thus far) just by jacking up the temp.

I actually think one or the more fun aspects of this pursuit is trying to be as smart as the machine. Not there yet, but who knows....

Phaedrux

@crchisholm said in What exactly does PID tuning do?:

I actually think one or the more fun aspects of this pursuit is trying to be as smart as the machine.

I couldn't agree more.

crchisholm

I may be hijacking my on thread, but would like to ask an unrelated question. Is there a G or M code that would lock the motors (especially Z). I keep moving the bed down by accident when working on there parts of the printer, and then have to relevel. Aggravating!

Phaedrux

@crchisholm said in What exactly does PID tuning do?:

I may be hijacking my on thread, but would like to ask an unrelated question. Is there a G or M code that would lock the motors (especially Z). I keep moving the bed down by accident when working on there parts of the printer, and then have to relevel. Aggravating!

Are your motors using idle current at that point?

Combination of M84 and M906 to set current.

https://duet3d.dozuki.com/Wiki/Gcode#Section_M84_Stop_idle_hold
https://duet3d.dozuki.com/Wiki/Gcode#Section_M906_Set_motor_currents

crchisholm

@phaedrux
Ok, does this look like the correct stratigy?

Created a macro 010_Freeze_Z_Axis with the following lines....

M84 Z

M906 Z:300
...assuming the motors are 1a and I only want to freeze Z.

Phaedrux

Not exactly. M84 basically turns the motors to a lower power mode so they are quieter and can cool off. So where you have M84 Z, that will basically turn the Z motor off, which is the opposite of what you want. M84 Sn sets the timer for how long it will sit idle before going to lower power. The amount of current used for this is set by M906 In which is a percentage of the normal current. So you'll want to set the amount of current to a level that will still keep the motor from turning when you press on the Z axis. Or alternatively, increase the idle time out so that the motors stay fully powered for longer, and therefore keep their holding power.

So maybe for you the best setup would be

M84 S600 ; set idle timeout to 10 minutes
M906 I50 ; set idle current to 50% of normal

crchisholm

@phaedrux I will try that. Thank you very much.

This mornings challenge seems to be understanding the M557 code to set the probe grid. Getting closer. Still getting results other than intended, but I guess that's to be expected when you don't expect the right thing.

Phaedrux

@crchisholm For the M557 it's important to keep the probe offset specified in the G31 command in mind when determining the grid extents.

crchisholm

@phaedrux ahhhh.... So when I enter the cordinates into the M557 command, am I entering the coordinates of the probe or the tip?

I'll bet that is where I am going wrong.

dc42

@crchisholm said in What exactly does PID tuning do?:

@phaedrux ahhhh.... So when I enter the cordinates into the M557 command, am I entering the coordinates of the probe or the tip?

I'll bet that is where I am going wrong.

They are the coordinates of the probe.

crchisholm

Ahhh....that explains why It would skip anything less than 30 in the X direction. My offset is X30 Y15. Should have figured that out. Thanks.